diff --git a/README.md b/README.md
index 6ec508d..c8bcc0f 100644
--- a/README.md
+++ b/README.md
@@ -24,10 +24,10 @@
 ```
 前端 (React + Vite)          后端 (NestJS)           数据库
 ┌─────────────────┐     ┌──────────────────┐     ┌──────────┐
-│ React 19        │     │ NestJS 11        │     │ SQLite   │
-│ Ant Design 6    │────▶│ TypeORM 0.3      │────▶│ (开发)   │
-│ ECharts         │     │ JWT + Passport   │     │ MySQL 8  │
-│ Vite 8          │     │ ExcelJS + PDFKit │     │ (生产)   │
+│ React 19        │     │ NestJS 11        │     │ MySQL 8  │
+│ Ant Design 6    │────▶│ TypeORM 0.3      │────▶│          │
+│ ECharts         │     │ JWT + Passport   │     │          │
+│ Vite 8          │     │ ExcelJS + PDFKit │     │          │
 └─────────────────┘     └──────────────────┘     └──────────┘
 ```
 
@@ -37,6 +37,7 @@
 
 - Node.js >= 18
 - npm >= 9
+- MySQL 8.0
 
 ### 后端启动
 
@@ -93,7 +94,7 @@ docker-compose up -d   # 一键启动 MySQL + 后端 + 前端
 
 | 配置项 | 说明 | 默认值 |
 |--------|------|--------|
-| `DB_TYPE` | 数据库类型 | `mysql` |
+| `DB_TYPE` | 数据库类型（仅支持 MySQL） | `mysql` |
 | `DB_HOST` | 数据库地址 | `localhost` |
 | `DB_PORT` | 数据库端口 | `3306` |
 | `DB_USERNAME` | 数据库用户名 | `dorm_billing` |
diff --git a/apps/server/datasource.ts b/apps/server/datasource.ts
index 7c1ea88..3263814 100644
--- a/apps/server/datasource.ts
+++ b/apps/server/datasource.ts
@@ -6,16 +6,14 @@ import { join } from 'path';
 const root = process.cwd();
 config({ path: join(root, '.env') });
 
-const dbType = process.env.DB_TYPE || 'sqlite';
-
 export default new DataSource({
-  type: dbType === 'mysql' ? 'mysql' : 'better-sqlite3',
-  host: dbType === 'mysql' ? (process.env.DB_HOST || 'localhost') : undefined,
-  port: dbType === 'mysql' ? (Number(process.env.DB_PORT) || 3306) : undefined,
-  username: dbType === 'mysql' ? (process.env.DB_USERNAME || 'root') : undefined,
-  password: dbType === 'mysql' ? (process.env.DB_PASSWORD || '') : undefined,
-  database: process.env.DB_DATABASE || (dbType === 'mysql' ? 'dorm_billing' : 'dorm_billing.db'),
-  charset: dbType === 'mysql' ? 'utf8mb4' : undefined,
+  type: 'mysql',
+  host: process.env.DB_HOST || 'localhost',
+  port: Number(process.env.DB_PORT) || 3306,
+  username: process.env.DB_USERNAME || 'root',
+  password: process.env.DB_PASSWORD || '',
+  database: process.env.DB_DATABASE || 'dorm_billing',
+  charset: 'utf8mb4',
   entities: [join(root, 'src/**/*.entity.ts')],
   migrations: [join(root, 'src/migrations/*.ts')],
 });
diff --git a/apps/server/package.json b/apps/server/package.json
index 1069ea5..beea8ec 100644
--- a/apps/server/package.json
+++ b/apps/server/package.json
@@ -65,16 +65,12 @@
     "rxjs": "^7.8.1",
     "typeorm": "^0.3.31"
   },
-  "optionalDependencies": {
-    "better-sqlite3": "^12.9.0"
-  },
   "devDependencies": {
     "@eslint/js": "^9.18.0",
     "@gongxue/typescript-config": "*",
     "@nestjs/cli": "^11.0.0",
     "@nestjs/schematics": "^11.0.0",
     "@nestjs/testing": "^11.0.1",
-    "@types/better-sqlite3": "^7.6.13",
     "@types/express": "^5.0.0",
     "@types/jest": "^30.0.0",
     "@types/node": "^24.0.0",
diff --git a/apps/server/src/ai-chat/ai-chat-enhancement.migration.spec.ts b/apps/server/src/ai-chat/ai-chat-enhancement.migration.spec.ts
deleted file mode 100644
index 3c21ee2..0000000
--- a/apps/server/src/ai-chat/ai-chat-enhancement.migration.spec.ts
+++ /dev/null
@@ -1,64 +0,0 @@
-import { DataSource } from 'typeorm';
-import { AddAiChat1784780000000 } from '../migrations/1784780000000-AddAiChat';
-import { EnhanceAiChatForAntDesignX1784860000000 } from '../migrations/1784860000000-EnhanceAiChatForAntDesignX';
-import { DropAiMessageFeedback1784920000000 } from '../migrations/1784920000000-DropAiMessageFeedback';
-
-describe('EnhanceAiChatForAntDesignX1784860000000', () => {
-  let dataSource: DataSource;
-
-  beforeEach(async () => {
-    dataSource = new DataSource({
-      type: 'better-sqlite3',
-      database: ':memory:',
-      migrations: [AddAiChat1784780000000, EnhanceAiChatForAntDesignX1784860000000],
-    });
-    await dataSource.initialize();
-    await dataSource.query(
-      'CREATE TABLE users (id integer PRIMARY KEY AUTOINCREMENT, username varchar(100) NOT NULL)',
-    );
-    await dataSource.query(
-      'CREATE TABLE ai_config (id integer PRIMARY KEY AUTOINCREMENT, singleton_key varchar(20) NOT NULL)',
-    );
-  });
-
-  afterEach(async () => {
-    if (dataSource.isInitialized) await dataSource.destroy();
-  });
-
-  it('adds Ant Design X chat fields and attachment relations', async () => {
-    await dataSource.runMigrations();
-    const runner = dataSource.createQueryRunner();
-    for (const table of ['ai_attachments', 'ai_message_attachments']) {
-      expect(await runner.hasTable(table)).toBe(true);
-    }
-    expect(await runner.hasColumn('ai_config', 'supports_vision')).toBe(true);
-    expect(await runner.hasColumn('ai_conversations', 'locked_skill_key')).toBe(true);
-    expect(await runner.hasColumn('ai_messages', 'feedback')).toBe(true);
-    expect(await runner.hasColumn('ai_tool_runs', 'skill_key')).toBe(true);
-    await runner.release();
-  });
-
-  it('drops the removed like/dislike feedback columns', async () => {
-    dataSource = new DataSource({
-      type: 'better-sqlite3',
-      database: ':memory:',
-      migrations: [
-        AddAiChat1784780000000,
-        EnhanceAiChatForAntDesignX1784860000000,
-        DropAiMessageFeedback1784920000000,
-      ],
-    });
-    await dataSource.initialize();
-    await dataSource.query(
-      'CREATE TABLE users (id integer PRIMARY KEY AUTOINCREMENT, username varchar(100) NOT NULL)',
-    );
-    await dataSource.query(
-      'CREATE TABLE ai_config (id integer PRIMARY KEY AUTOINCREMENT, singleton_key varchar(20) NOT NULL)',
-    );
-    await dataSource.runMigrations();
-    const runner = dataSource.createQueryRunner();
-    expect(await runner.hasColumn('ai_messages', 'feedback')).toBe(false);
-    expect(await runner.hasColumn('ai_messages', 'feedback_reason')).toBe(false);
-    await runner.release();
-  });
-});
diff --git a/apps/server/src/ai-chat/ai-chat.migration.spec.ts b/apps/server/src/ai-chat/ai-chat.migration.spec.ts
deleted file mode 100644
index 2087572..0000000
--- a/apps/server/src/ai-chat/ai-chat.migration.spec.ts
+++ /dev/null
@@ -1,46 +0,0 @@
-import { DataSource } from 'typeorm';
-import { AddAiChat1784780000000 } from '../migrations/1784780000000-AddAiChat';
-
-describe('AddAiChat1784780000000', () => {
-  let dataSource: DataSource;
-
-  beforeEach(async () => {
-    dataSource = new DataSource({
-      type: 'better-sqlite3',
-      database: ':memory:',
-      migrations: [AddAiChat1784780000000],
-    });
-    await dataSource.initialize();
-    await dataSource.query(
-      'CREATE TABLE users (id integer PRIMARY KEY AUTOINCREMENT, username varchar(100) NOT NULL)',
-    );
-  });
-
-  afterEach(async () => {
-    if (dataSource.isInitialized) await dataSource.destroy();
-  });
-
-  it('创建会话、消息和工具记录表，并按会话级联删除', async () => {
-    await dataSource.runMigrations();
-
-    for (const table of ['ai_conversations', 'ai_messages', 'ai_tool_runs']) {
-      expect(await dataSource.createQueryRunner().hasTable(table)).toBe(true);
-    }
-
-    await dataSource.query("INSERT INTO users (username) VALUES ('tester')");
-    await dataSource.query(
-      "INSERT INTO ai_conversations (user_id, title) VALUES (1, '测试会话')",
-    );
-    await dataSource.query(
-      "INSERT INTO ai_messages (conversation_id, role, content) VALUES (1, 'assistant', '回答')",
-    );
-    await dataSource.query(
-      "INSERT INTO ai_tool_runs (message_id, tool_call_id, tool_name, status) VALUES (1, 'call_1', 'search_students', 'success')",
-    );
-
-    await dataSource.query('DELETE FROM ai_conversations WHERE id = 1');
-
-    expect(await dataSource.query('SELECT id FROM ai_messages')).toEqual([]);
-    expect(await dataSource.query('SELECT id FROM ai_tool_runs')).toEqual([]);
-  });
-});
diff --git a/apps/server/src/ai-chat/ai-review-enlarge.migration.spec.ts b/apps/server/src/ai-chat/ai-review-enlarge.migration.spec.ts
deleted file mode 100644
index 6db122c..0000000
--- a/apps/server/src/ai-chat/ai-review-enlarge.migration.spec.ts
+++ /dev/null
@@ -1,63 +0,0 @@
-import { DataSource } from 'typeorm';
-import { AddA2UiReviews1784880000000 } from '../migrations/1784880000000-AddA2UiReviews';
-import { EnlargeAiReviewSections1784900000000 } from '../migrations/1784900000000-EnlargeAiReviewSections';
-
-describe('EnlargeAiReviewSections1784900000000', () => {
-  let dataSource: DataSource;
-
-  beforeEach(async () => {
-    dataSource = new DataSource({
-      type: 'better-sqlite3',
-      database: ':memory:',
-      migrations: [AddA2UiReviews1784880000000, EnlargeAiReviewSections1784900000000],
-    });
-    await dataSource.initialize();
-    await dataSource.query(`
-      CREATE TABLE ai_messages (
-        id integer PRIMARY KEY AUTOINCREMENT,
-        conversation_id integer NOT NULL,
-        role varchar(20) NOT NULL,
-        content text,
-        reasoning_content text,
-        status varchar(20) NOT NULL,
-        error_code varchar(50),
-        reply_to_message_id integer,
-        feedback varchar(10),
-        feedback_reason varchar(500),
-        metadata text,
-        created_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
-        updated_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP
-      )
-    `);
-  });
-
-  afterEach(async () => {
-    if (dataSource.isInitialized) await dataSource.destroy();
-  });
-
-  it('迁移后可保存远超 256KB 的预览数据，且再次执行幂等', async () => {
-    await dataSource.runMigrations();
-    await dataSource.runMigrations();
-
-    await dataSource.query(
-      `INSERT INTO ai_messages (conversation_id, role, content, status)
-       VALUES (1, 'assistant', '', 'completed')`,
-    );
-    const big = '中'.repeat(300 * 1024);
-    await dataSource.query(
-      `INSERT INTO ai_reviews
-        (id, conversation_id, user_id, assistant_message_id, title, sections_json, status)
-       VALUES (?, ?, ?, ?, ?, ?, ?)`,
-      ['review-1', 1, 1, 1, '大体积导入', big, 'pending'],
-    );
-    const rows: Array<{ sections_json: string }> = await dataSource.query(
-      'SELECT sections_json FROM ai_reviews WHERE id = ?',
-      ['review-1'],
-    );
-    expect(rows[0].sections_json.length).toBe(big.length);
-
-    const runner = dataSource.createQueryRunner();
-    expect(await runner.hasColumn('ai_reviews', 'sections_json')).toBe(true);
-    await runner.release();
-  });
-});
diff --git a/apps/server/src/ai-chat/ai-review.service.spec.ts b/apps/server/src/ai-chat/ai-review.service.spec.ts
index 4b327a4..1ce6b94 100644
--- a/apps/server/src/ai-chat/ai-review.service.spec.ts
+++ b/apps/server/src/ai-chat/ai-review.service.spec.ts
@@ -637,696 +637,3 @@ describe('AiReviewService', () => {
   });
 });
 
-describe('AiReviewService.submit (real sqlite transaction)', () => {
-  let dataSource: DataSource;
-  let service: AiReviewService;
-  let hostOrg: Organization;
-  let namedOrg: Organization;
-  let assistantMessageId: number;
-
-  beforeAll(async () => {
-    dataSource = new DataSource({
-      type: 'better-sqlite3',
-      database: ':memory:',
-      entities: Object.values(allEntities).filter(
-        (value): value is new (...args: unknown[]) => unknown =>
-          typeof value === 'function',
-      ),
-      synchronize: true,
-    });
-    await dataSource.initialize();
-    const orgRepo = dataSource.getRepository(Organization);
-    hostOrg = await orgRepo.save(
-      orgRepo.create({ publicId: 'host', code: 'HOST', name: '恭学总校', isHost: true }),
-    );
-    namedOrg = await orgRepo.save(
-      orgRepo.create({ publicId: 'org-a', code: 'ORG_A', name: '东校区' }),
-    );
-    const userRepo = dataSource.getRepository(User);
-    const user = await userRepo.save(
-      userRepo.create({ username: 'review-tester', passwordHash: 'x' }),
-    );
-    const conversationRepo = dataSource.getRepository(AiConversation);
-    const conversation = await conversationRepo.save(
-      conversationRepo.create({ userId: user.id, title: '测试会话' }),
-    );
-    const messageRepo = dataSource.getRepository(AiMessage);
-    const assistant = await messageRepo.save(
-      messageRepo.create({
-        conversationId: conversation.id,
-        role: 'assistant',
-        content: '',
-        status: 'completed',
-      }),
-    );
-    assistantMessageId = assistant.id;
-    const reviewRepo = dataSource.getRepository(AiReview);
-    service = new AiReviewService(reviewRepo, dataSource);
-  });
-
-  afterAll(async () => {
-    await dataSource.destroy();
-  });
-
-  it('按 学生→宿舍→换宿 顺序事务入库，并收集逐行问题', async () => {
-    const studentRepo = dataSource.getRepository(Student);
-    const roomRepo = dataSource.getRepository(Room);
-    const bedRepo = dataSource.getRepository(Bed);
-    const occRepo = dataSource.getRepository(Occupancy);
-
-    const existing = await studentRepo.save(
-      studentRepo.create({
-        name: '老王',
-        phone: '13800138000',
-        studentNo: 'S001',
-        organizationId: hostOrg.id,
-      }),
-    );
-    const oldRoom = await roomRepo.save(
-      roomRepo.create({ roomNumber: '1-101', capacity: 4, status: 'available' }),
-    );
-    await bedRepo.save(
-      Array.from({ length: 4 }, (_, index) =>
-        bedRepo.create({ roomId: oldRoom.id, bedNumber: `${index + 1}号床` }),
-      ),
-    );
-    await occRepo.save(
-      occRepo.create({
-        studentId: existing.id,
-        roomId: oldRoom.id,
-        checkInDate: '2026-01-05',
-        billingStartDate: '2026-01-05',
-        stayType: 'short',
-        responsibleOrganizationId: hostOrg.id,
-      }),
-    );
-
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '开学导入',
-        summary: 'Excel 导入',
-        sections: [
-          {
-            key: 'students',
-            title: '学生',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-              { key: 'organization', title: '机构' },
-            ],
-            rows: [
-              { name: '张三', phone: '13900139000', organization: '东校区' },
-              { name: '老王', phone: '13800138000', organization: '恭学总校' },
-              { name: '李四', phone: '13700137000', organization: '不存在的机构' },
-            ],
-            issues: [],
-          },
-          {
-            key: 'rooms',
-            title: '宿舍',
-            kind: 'table',
-            columns: [{ key: 'roomNumber', title: '房间号' }],
-            rows: [{ roomNumber: '3-301' }, { roomNumber: '1-101' }],
-            issues: [],
-          },
-          {
-            key: 'transfers',
-            title: '换宿',
-            kind: 'table',
-            columns: [
-              { key: 'studentNo', title: '学号' },
-              { key: 'oldRoom', title: '原宿舍' },
-              { key: 'newRoom', title: '目标宿舍' },
-              { key: 'transferDate', title: '换宿日期' },
-            ],
-            rows: [
-              { studentNo: 'S001', oldRoom: '1-101', newRoom: '3-301', transferDate: '2026-03-01' },
-            ],
-            issues: [],
-          },
-        ],
-      },
-    );
-
-    const { review: submittedReview, result } = await service.submitAll(review.id, 7);
-    expect(result.students.created).toBe(2);
-    expect(result.students.skipped).toBe(1);
-    expect(result.rooms.created).toBe(1);
-    expect(result.rooms.skipped).toBe(1);
-    expect(result.transfers.completed).toBe(1);
-    expect(result.transfers.skipped).toBe(0);
-
-    const createdStudent = await studentRepo.findOne({ where: { phone: '13900139000' } });
-    expect(createdStudent?.name).toBe('张三');
-    expect(createdStudent?.organizationId).toBe(namedOrg.id);
-    const hostFallbackStudent = await studentRepo.findOne({ where: { phone: '13700137000' } });
-    expect(hostFallbackStudent?.organizationId).toBe(hostOrg.id);
-
-    const newRoom = await roomRepo.findOne({ where: { roomNumber: '3-301' } });
-    expect(newRoom?.capacity).toBe(4);
-    expect(await bedRepo.count({ where: { roomId: newRoom!.id } })).toBe(4);
-
-    const oldOcc = await occRepo.findOne({
-      where: { studentId: existing.id, roomId: oldRoom.id },
-    });
-    expect(oldOcc?.checkOutDate).toBe('2026-03-01');
-    const newOcc = await occRepo.findOne({
-      where: { studentId: existing.id, roomId: newRoom!.id, checkOutDate: null },
-    });
-    expect(newOcc?.checkInDate).toBe('2026-03-01');
-    expect(newOcc?.billingStartDate).toBe('2026-03-02');
-
-    expect(submittedReview.status).toBe('submitted');
-    expect(submittedReview.submittedAt).toBeInstanceOf(Date);
-    const savedSections = service.parseSections(submittedReview.sectionsJson);
-    const studentSection = savedSections.find((section) => section.key === 'students');
-    expect(studentSection?.issues).toEqual(
-      expect.arrayContaining(['学生「老王」已存在（按手机号/学号匹配），未重复创建']),
-    );
-    expect(submittedReview.resultSummary).toContain('成功导入学生 2 人');
-  });
-
-  it('入住记录分表：学生和宿舍不存在时自动创建后写入住记录', async () => {
-    const studentRepo = dataSource.getRepository(Student);
-    const roomRepo = dataSource.getRepository(Room);
-    const occRepo = dataSource.getRepository(Occupancy);
-
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '入住导入',
-        summary: '宿舍入住记录',
-        sections: [
-          {
-            key: 'checkins',
-            title: '入住记录',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-              { key: 'roomNumber', title: '宿舍号' },
-              { key: 'checkInDate', title: '入住日期' },
-            ],
-            rows: [
-              {
-                name: '於嘉丽',
-                phone: '13611112222',
-                roomNumber: '5-501',
-                checkInDate: '2026-08-01',
-              },
-              {
-                name: '重复学生',
-                phone: '13611112222',
-                roomNumber: '5-502',
-                checkInDate: '2026-08-01',
-              },
-            ],
-            issues: [],
-          },
-        ],
-      },
-    );
-
-    const { result } = await service.submitAll(review.id, 7);
-    expect(result.checkins.completed).toBe(1);
-    expect(result.checkins.skipped).toBe(1);
-
-    const created = await studentRepo.findOne({ where: { phone: '13611112222' } });
-    expect(created?.name).toBe('於嘉丽');
-    expect(created?.organizationId).toBe(hostOrg.id);
-    const room = await roomRepo.findOne({ where: { roomNumber: '5-501' } });
-    expect(room?.capacity).toBe(4);
-    const occupancy = await occRepo.findOne({ where: { studentId: created!.id } });
-    expect(occupancy?.checkInDate).toBe('2026-08-01');
-    expect(occupancy?.roomId).toBe(room!.id);
-  });
-
-  it('分步确认：依赖未满足拒绝，重复确认 409，全部完成后整卡提交', async () => {
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '分步导入',
-        sections: [
-          {
-            key: 'students',
-            title: '学生',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [{ name: '分步学生', phone: '13511112222' }],
-            issues: [],
-          },
-          {
-            key: 'rooms',
-            title: '宿舍',
-            kind: 'table',
-            columns: [{ key: 'roomNumber', title: '房间号' }],
-            rows: [{ roomNumber: '9-901' }],
-            issues: [],
-          },
-          {
-            key: 'transfers',
-            title: '换宿',
-            kind: 'table',
-            columns: [{ key: 'studentNo', title: '学号' }],
-            rows: [{ studentNo: 'NOPE' }],
-            issues: [],
-          },
-        ],
-      },
-    );
-
-    await expect(service.submitSection(review.id, 7, 'transfers')).rejects.toMatchObject({
-      message: expect.stringContaining('请先确认第 1 步'),
-    });
-
-    const studentsStep = await service.submitSection(review.id, 7, 'students');
-    expect(studentsStep.result).toMatchObject({ created: 1, skipped: 0 });
-    expect(
-      service
-        .parseSections(studentsStep.review.sectionsJson)
-        .find((section) => section.key === 'students')?.status,
-    ).toBe('submitted');
-
-    await expect(service.submitSection(review.id, 7, 'students')).rejects.toMatchObject({
-      message: expect.stringContaining('已确认导入'),
-    });
-
-    await service.submitSection(review.id, 7, 'rooms');
-    const transferStep = await service.submitSection(review.id, 7, 'transfers');
-    expect(service.parseSections(transferStep.review.sectionsJson).map((s) => s.status)).toEqual([
-      'submitted',
-      'submitted',
-      'submitted',
-    ]);
-    expect(transferStep.review.status).toBe('submitted');
-    expect(transferStep.review.submittedAt).toBeInstanceOf(Date);
-  });
-
-  it('依赖按类型整组判断：同类型全部 sheet 提交后才允许换宿', async () => {
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '多 sheet 依赖',
-        sections: [
-          {
-            key: 'students_a',
-            title: '学生 A',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [{ name: '甲', phone: '13511112222' }],
-            issues: [],
-          },
-          {
-            key: 'students_b',
-            title: '学生 B',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [{ name: '乙', phone: '13511113333' }],
-            issues: [],
-          },
-          {
-            key: 'rooms_9',
-            title: '9 号楼宿舍',
-            kind: 'table',
-            columns: [{ key: 'roomNumber', title: '房间号' }],
-            rows: [{ roomNumber: '9-901' }],
-            issues: [],
-          },
-          {
-            key: 'checkins_active',
-            type: 'checkins',
-            title: '在住记录',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-              { key: 'roomNumber', title: '宿舍号' },
-              { key: 'checkInDate', title: '入住日期' },
-            ],
-            rows: [
-              {
-                name: '丙',
-                phone: '13511115555',
-                roomNumber: '9-903',
-                checkInDate: '2026-08-01',
-              },
-            ],
-            issues: [],
-          },
-          {
-            key: 'transfers_9',
-            title: '换宿',
-            kind: 'table',
-            columns: [
-              { key: 'studentPhone', title: '手机号' },
-              { key: 'newRoom', title: '目标宿舍' },
-              { key: 'transferDate', title: '换宿日期' },
-            ],
-            rows: [{ studentPhone: '13511115555', newRoom: '9-901', transferDate: '2026-08-10' }],
-            issues: [],
-          },
-        ],
-      },
-    );
-
-    await expect(service.submitSection(review.id, 7, 'transfers_9')).rejects.toMatchObject({
-      message: expect.stringContaining('请先确认第 1 步'),
-    });
-
-    await service.submitSection(review.id, 7, 'students_a');
-    await expect(service.submitSection(review.id, 7, 'transfers_9')).rejects.toMatchObject({
-      message: expect.stringContaining('请先确认第 2 步'),
-    });
-
-    await service.submitSection(review.id, 7, 'students_b');
-    await service.submitSection(review.id, 7, 'rooms_9');
-    await service.submitSection(review.id, 7, 'checkins_active');
-    const transferStep = await service.submitSection(review.id, 7, 'transfers_9');
-    expect(transferStep.result).toMatchObject({ completed: 1, skipped: 0 });
-    const statuses = service
-      .parseSections(transferStep.review.sectionsJson)
-      .map((section) => section.status);
-    expect(statuses).toEqual(['submitted', 'submitted', 'submitted', 'submitted', 'submitted']);
-  });
-
-  it('组确认按 sheet 逐张导入，成功后整组状态已导入', async () => {
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '整组入住确认',
-        sections: Array.from({ length: 2 }, (_, i) => ({
-          key: `checkins_group_${i + 1}`,
-          type: 'checkins',
-          title: `入住表${i + 1}`,
-          kind: 'table',
-          columns: [
-            { key: 'name', title: '姓名' },
-            { key: 'phone', title: '手机号' },
-            { key: 'roomNumber', title: '宿舍号' },
-            { key: 'checkInDate', title: '入住日期' },
-          ],
-          rows: [
-            {
-              name: `入住学生${i + 1}`,
-              phone: `1360000000${i + 1}`,
-              roomNumber: `5-50${i + 1}`,
-              checkInDate: '2026-08-01',
-            },
-          ],
-          issues: [],
-        })),
-      },
-    );
-
-    const { review: grouped } = await service.submitGroup(review.id, 7, 'checkins');
-    const sections = service.parseSections(grouped.sectionsJson);
-    expect(sections.map((section) => section.status)).toEqual(['submitted', 'submitted']);
-    expect(grouped.status).toBe('submitted');
-    expect(
-      await dataSource.getRepository(Student).count({
-        where: { phone: '13600000001' },
-      }),
-    ).toBe(1);
-    expect(
-      await dataSource.getRepository(Student).count({
-        where: { phone: '13600000002' },
-      }),
-    ).toBe(1);
-    expect(await dataSource.getRepository(Room).count({ where: { roomNumber: '5-501' } })).toBe(1);
-    expect(await dataSource.getRepository(Room).count({ where: { roomNumber: '5-502' } })).toBe(1);
-  });
-
-  it('全部确认时按类型合并多张 sheet 的统计数量', async () => {
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '多 sheet 聚合',
-        sections: Array.from({ length: 2 }, (_, i) => ({
-          key: `students_batch_${i + 1}`,
-          type: 'students',
-          title: `学生表${i + 1}`,
-          kind: 'table',
-          columns: [
-            { key: 'name', title: '姓名' },
-            { key: 'phone', title: '手机号' },
-          ],
-          rows: [
-            {
-              name: `批量学生${i + 1}`,
-              phone: `1370000000${i + 1}`,
-            },
-          ],
-          issues: [],
-        })),
-      },
-    );
-
-    const { result } = await service.submitAll(review.id, 7);
-    expect(result.students.created).toBe(2);
-    expect(result.students.skipped).toBe(0);
-    expect(result.message).toContain('成功导入学生 2 人');
-  });
-
-  it('组确认依赖未满足时返回 409，不导入任何 sheet', async () => {
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '组依赖校验',
-        sections: [
-          {
-            key: 'students_a',
-            title: '学生 A',
-            kind: 'table',
-            columns: [{ key: 'name', title: '姓名' }],
-            rows: [{ name: '甲' }],
-            issues: [],
-          },
-          {
-            key: 'transfers_a',
-            title: '换宿 A',
-            kind: 'table',
-            columns: [{ key: 'studentPhone', title: '手机号' }],
-            rows: [{ studentPhone: '13511114444' }],
-            issues: [],
-          },
-        ],
-      },
-    );
-    await expect(service.submitGroup(review.id, 7, 'transfers')).rejects.toMatchObject({
-      message: expect.stringContaining('请先确认第 1 步'),
-    });
-    const sections = service.parseSections((await service.findOwned(review.id, 7)).sectionsJson);
-    expect(sections.map((section) => section.status)).toEqual(['pending', 'pending']);
-  });
-
-  it('单步确认部分成功时持久化 resultSummary 与问题', async () => {
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '部分成功',
-        sections: [
-          {
-            key: 'students',
-            title: '学生',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [
-              { name: '新学生', phone: '13522223333' },
-              { name: '重复学生', phone: '13522223333' },
-            ],
-            issues: [],
-          },
-        ],
-      },
-    );
-
-    const step = await service.submitSection(review.id, 7, 'students');
-    expect(step.result).toMatchObject({ created: 1, skipped: 1 });
-    const saved = await service.findOwned(review.id, 7);
-    const section = service.parseSections(saved.sectionsJson)[0];
-    expect(section.status).toBe('submitted');
-    expect(section.resultSummary).toContain('成功导入学生 1 人，跳过 1 条');
-    expect(section.issues).toEqual(
-      expect.arrayContaining([expect.stringContaining('同一批次中的其他学生')]),
-    );
-    expect(saved.status).toBe('submitted');
-  });
-
-  it('全部确认按固定依赖顺序提交，不受 sections 原始顺序影响', async () => {
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '乱序导入',
-        sections: [
-          {
-            key: 'transfers',
-            title: '换宿',
-            kind: 'table',
-            columns: [{ key: 'studentNo', title: '学号' }],
-            rows: [{ studentNo: 'NOPE' }],
-            issues: [],
-          },
-          {
-            key: 'students',
-            title: '学生',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [{ name: '乱序学生', phone: '13544445555' }],
-            issues: [],
-          },
-          {
-            key: 'rooms',
-            title: '宿舍',
-            kind: 'table',
-            columns: [{ key: 'roomNumber', title: '房间号' }],
-            rows: [{ roomNumber: '9-902' }],
-            issues: [],
-          },
-        ],
-      },
-    );
-
-    const { review: completed } = await service.submitAll(review.id, 7);
-    expect(completed.status).toBe('submitted');
-    expect(service.parseSections(completed.sectionsJson).map((section) => section.status)).toEqual([
-      'submitted',
-      'submitted',
-      'submitted',
-    ]);
-  });
-
-  it('旧数据缺少 section status 字段时默认 pending 并可继续确认', async () => {
-    const review = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: '旧数据兼容',
-        sections: [
-          {
-            key: 'students',
-            title: '学生',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [{ name: '旧数据学生', phone: '13533334444' }],
-            issues: [],
-          },
-        ],
-      },
-    );
-    const legacySections = service
-      .parseSections(review.sectionsJson)
-      .map(
-        ({ status: _status, resultSummary: _result, submittedAt: _at, type: _type, ...rest }) =>
-          rest,
-      );
-    review.sectionsJson = JSON.stringify(legacySections);
-    await dataSource.getRepository(AiReview).save(review);
-
-    const step = await service.submitSection(review.id, 7, 'students');
-    expect(step.result).toMatchObject({ created: 1, skipped: 0 });
-    const reloaded = service.parseSections((await service.findOwned(review.id, 7)).sectionsJson)[0];
-    expect(reloaded.status).toBe('submitted');
-  });
-
-  it('同会话生成新预览后旧预览过期，且所有确认入口拒绝', async () => {
-    const conversationId = 9001;
-    const first = await service.createReview(
-      { ...baseArgs, conversationId, assistantMessageId },
-      {
-        title: '旧预览',
-        sections: [
-          {
-            key: 'students',
-            title: '学生',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [{ name: '旧学生', phone: '13711110001' }],
-            issues: [],
-          },
-        ],
-      },
-    );
-    const second = await service.createReview(
-      { ...baseArgs, conversationId, assistantMessageId },
-      {
-        title: '新预览',
-        sections: [
-          {
-            key: 'students',
-            title: '学生',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [{ name: '新学生', phone: '13711110002' }],
-            issues: [],
-          },
-        ],
-      },
-    );
-
-    const expired = await service.expirePreviousReviews(7, conversationId, second.id);
-    expect(expired.map((review) => review.id)).toEqual([first.id]);
-    expect((await service.findOwned(first.id, 7)).status).toBe('expired');
-    expect((await service.findOwned(second.id, 7)).status).toBe('pending');
-
-    await expect(service.findOwnedPending(first.id, 7)).rejects.toThrow('已失效');
-    await expect(service.submitSection(first.id, 7, 'students')).rejects.toMatchObject({
-      message: expect.stringContaining('已失效'),
-    });
-    await expect(service.submitGroup(first.id, 7, 'students')).rejects.toMatchObject({
-      message: expect.stringContaining('已失效'),
-    });
-    await expect(service.submitAll(first.id, 7)).rejects.toMatchObject({
-      message: expect.stringContaining('已失效'),
-    });
-  });
-
-  it('不同会话的旧预览不会被其他会话的新预览过期', async () => {
-    const first = await service.createReview(
-      { ...baseArgs, assistantMessageId },
-      {
-        title: 'A 会话预览',
-        sections: [
-          {
-            key: 'students',
-            title: '学生',
-            kind: 'table',
-            columns: [
-              { key: 'name', title: '姓名' },
-              { key: 'phone', title: '手机号' },
-            ],
-            rows: [{ name: '跨会话学生', phone: '13711110003' }],
-            issues: [],
-          },
-        ],
-      },
-    );
-
-    await service.expirePreviousReviews(7, 999, 'other-review');
-    expect((await service.findOwned(first.id, 7)).status).toBe('pending');
-  });
-});
diff --git a/apps/server/src/ai-config/ai-config.service.ts b/apps/server/src/ai-config/ai-config.service.ts
index 4536948..1f3bd6a 100644
--- a/apps/server/src/ai-config/ai-config.service.ts
+++ b/apps/server/src/ai-config/ai-config.service.ts
@@ -78,8 +78,7 @@ export class AiConfigService implements AiConfigProbeContext {
         const code = isErrWithCode ? (err as Record<string, unknown>).code : undefined;
         const errno = isErrWithCode ? (err as Record<string, unknown>).errno : undefined;
         // MySQL: ER_DUP_ENTRY (code 'ER_DUP_ENTRY') or errno 1062
-        // SQLite: SQLITE_CONSTRAINT (code 'SQLITE_CONSTRAINT')
-        if (code === 'ER_DUP_ENTRY' || errno === 1062 || code === 'SQLITE_CONSTRAINT') {
+        if (code === 'ER_DUP_ENTRY' || errno === 1062) {
           const existing = await this.repo.findOne({ where: { singletonKey: SINGLETON_KEY } });
           if (existing) return existing;
         }
diff --git a/apps/server/src/app.module.ts b/apps/server/src/app.module.ts
index c90aca7..0cd513c 100644
--- a/apps/server/src/app.module.ts
+++ b/apps/server/src/app.module.ts
@@ -91,7 +91,6 @@ import { IntegrationConfigModule } from './integration/config/config.module';
       imports: [ConfigModule],
       inject: [ConfigService],
       useFactory: (config: ConfigService): TypeOrmModuleOptions => {
-        const dbType = config.get('DB_TYPE', 'sqlite');
         const allEntities = [
           Entities.Student,
           Entities.Room,
@@ -151,26 +150,17 @@ import { IntegrationConfigModule } from './integration/config/config.module';
           Entities.ImportStep,
           Entities.ImportRow,
         ];
-        if (dbType === 'mysql') {
-          return {
-            type: 'mysql' as const,
-            host: config.get('DB_HOST', 'localhost'),
-            port: config.get<number>('DB_PORT', 3306),
-            username: config.get('DB_USERNAME', 'root'),
-            password: config.get<string>('DB_PASSWORD', ''),
-            database: config.get<string>('DB_DATABASE', 'dorm_billing'),
-            entities: allEntities,
-            migrations: allMigrations,
-            synchronize: config.get('DB_SYNCHRONIZE', 'true') !== 'false',
-            charset: 'utf8mb4',
-          };
-        }
         return {
-          type: 'better-sqlite3' as const,
-          database: config.get<string>('DB_DATABASE', 'dorm_billing.db'),
-          migrations: allMigrations,
+          type: 'mysql' as const,
+          host: config.get('DB_HOST', 'localhost'),
+          port: config.get<number>('DB_PORT', 3306),
+          username: config.get('DB_USERNAME', 'root'),
+          password: config.get<string>('DB_PASSWORD', ''),
+          database: config.get<string>('DB_DATABASE', 'dorm_billing'),
           entities: allEntities,
+          migrations: allMigrations,
           synchronize: config.get('DB_SYNCHRONIZE', 'true') !== 'false',
+          charset: 'utf8mb4',
         };
       },
     }),
diff --git a/apps/server/src/attendance/attendance-lesson.service.ts b/apps/server/src/attendance/attendance-lesson.service.ts
index 632f6c2..5dafa4a 100644
--- a/apps/server/src/attendance/attendance-lesson.service.ts
+++ b/apps/server/src/attendance/attendance-lesson.service.ts
@@ -244,8 +244,8 @@ export class AttendanceLessonService {
       } catch (err: unknown) {
         const code = (err as Record<string, unknown>).code;
         const errno = (err as Record<string, unknown>).errno;
-        // MySQL: ER_DUP_ENTRY or errno 1062; SQLite: SQLITE_CONSTRAINT
-        if (code === 'ER_DUP_ENTRY' || errno === 1062 || code === 'SQLITE_CONSTRAINT') {
+        // MySQL: ER_DUP_ENTRY or errno 1062
+        if (code === 'ER_DUP_ENTRY' || errno === 1062) {
           const existing = await sessionRepo.findOne({
             where: { scheduleId, lessonDate },
           });
diff --git a/apps/server/src/attendance/attendance-workflow.integration.spec.ts b/apps/server/src/attendance/attendance-workflow.integration.spec.ts
deleted file mode 100644
index 9fb9de2..0000000
--- a/apps/server/src/attendance/attendance-workflow.integration.spec.ts
+++ /dev/null
@@ -1,332 +0,0 @@
-import type { INestApplication } from '@nestjs/common';
-import { Test } from '@nestjs/testing';
-import { getRepositoryToken } from '@nestjs/typeorm';
-import request from 'supertest';
-import type { Repository } from 'typeorm';
-import { AppModule } from '../app.module';
-import type { DingTalkAttendanceResult } from '../integration/dingtalk.service';
-import { DingTalkService } from '../integration/dingtalk.service';
-import {
-  AttendanceRecord,
-  Organization,
-  Role,
-  Student,
-  StudentDingMapping,
-  User,
-} from '../entities';
-import { createStudentImportTemplateWorkbook } from '../students/student-import';
-
-const LESSON_DATE = new Intl.DateTimeFormat('en-CA', {
-  timeZone: 'Asia/Shanghai',
-  year: 'numeric',
-  month: '2-digit',
-  day: '2-digit',
-}).format(new Date());
-const STUDENT_A_DING_ID = 'integration-student-a';
-const STUDENT_B_DING_ID = 'integration-student-b';
-
-const auth = (token: string) => ({ Authorization: `Bearer ${token}` });
-
-function chinaWeekDay(date: string): number {
-  const day = new Date(`${date}T00:00:00+08:00`).getDay();
-  return day === 0 ? 7 : day;
-}
-
-function attendanceResult(
-  userId: string,
-  checkId: string,
-  actualCheckTime: string,
-): DingTalkAttendanceResult {
-  return {
-    userId,
-    userName: '',
-    workDate: LESSON_DATE,
-    timeResult: 'Normal',
-    locationResult: 'Normal',
-    planCheckTime: `${LESSON_DATE}T00:00:00+08:00`,
-    actualCheckTime,
-    checkId,
-    checkType: 'OnDuty',
-    sourceType: 'ATM',
-    deviceName: '集成测试考勤机',
-    deviceId: 'integration-device',
-  };
-}
-
-// Requires a fully configured attendance integration and is intentionally excluded from routine CI.
-describe.skip('attendance workflow integration', () => {
-  let app: INestApplication;
-  let adminToken: string;
-  let teacherToken: string;
-  let mockedPunches: DingTalkAttendanceResult[];
-  const originalEnv = {
-    DB_TYPE: process.env.DB_TYPE,
-    DB_DATABASE: process.env.DB_DATABASE,
-    DB_SYNCHRONIZE: process.env.DB_SYNCHRONIZE,
-    SEED_DEV: process.env.SEED_DEV,
-    ADMIN_PASSWORD: process.env.ADMIN_PASSWORD,
-  };
-
-  beforeAll(async () => {
-    process.env.DB_TYPE = 'sqlite';
-    process.env.DB_DATABASE = ':memory:';
-    process.env.DB_SYNCHRONIZE = 'true';
-    process.env.SEED_DEV = 'true';
-    process.env.ADMIN_PASSWORD = 'admin123';
-
-    mockedPunches = [];
-    const dingTalk = {
-      fetchAttendanceResults: jest.fn(async () => mockedPunches),
-    };
-
-    const moduleRef = await Test.createTestingModule({ imports: [AppModule] })
-      .overrideProvider(DingTalkService)
-      .useValue(dingTalk)
-      .compile();
-
-    app = moduleRef.createNestApplication();
-    app.setGlobalPrefix('api');
-    await app.init();
-
-    const login = await request(app.getHttpServer())
-      .post('/api/auth/login')
-      .send({ username: 'admin', password: 'admin123' })
-      .expect(201);
-    adminToken = login.body.access_token;
-  });
-
-  afterAll(async () => {
-    await app?.close();
-    for (const [key, value] of Object.entries(originalEnv)) {
-      if (value === undefined) delete process.env[key];
-      else process.env[key] = value;
-    }
-  });
-
-  it('imports students, builds a teacher class schedule, refreshes punches, and scopes reads', async () => {
-    const roleRepo = app.get<Repository<Role>>(getRepositoryToken(Role));
-    const userRepo = app.get<Repository<User>>(getRepositoryToken(User));
-    const studentRepo = app.get<Repository<Student>>(getRepositoryToken(Student));
-    const mappingRepo = app.get<Repository<StudentDingMapping>>(
-      getRepositoryToken(StudentDingMapping),
-    );
-    const organizationRepo = app.get<Repository<Organization>>(getRepositoryToken(Organization));
-    const attendanceRepo = app.get<Repository<AttendanceRecord>>(
-      getRepositoryToken(AttendanceRecord),
-    );
-
-    const teacherRole = await roleRepo.findOneByOrFail({ code: 'teacher' });
-    const teacherCreate = await request(app.getHttpServer())
-      .post('/api/rbac/users')
-      .set(auth(adminToken))
-      .send({
-        username: 'integration-teacher',
-        password: 'teacher123',
-        name: '集成测试任课教师',
-        roleIds: [teacherRole.id],
-      })
-      .expect(201);
-    expect(teacherCreate.body.message).toBe('用户创建成功');
-
-    const teacher = await userRepo.findOneByOrFail({ username: 'integration-teacher' });
-    const teacherId = teacher.id;
-    const teacherLogin = await request(app.getHttpServer())
-      .post('/api/auth/login')
-      .send({ username: 'integration-teacher', password: 'teacher123' })
-      .expect(201);
-    teacherToken = teacherLogin.body.access_token;
-
-    const host = await organizationRepo.findOneByOrFail({ isHost: true, status: 'active' });
-    const workbook = createStudentImportTemplateWorkbook();
-    const sheet = workbook.getWorksheet('学生基础+档案+录取')!;
-    sheet.spliceRows(2, 1);
-    sheet.addRow({
-      phone: '13800000001',
-      name: '集成学生甲',
-      studentNo: 'IT001',
-      organization: host.name,
-    });
-    sheet.addRow({
-      phone: '13800000002',
-      name: '集成学生乙',
-      studentNo: 'IT002',
-      organization: host.name,
-    });
-    const workbookBuffer = Buffer.from(await workbook.xlsx.writeBuffer());
-
-    const importResult = await request(app.getHttpServer())
-      .post('/api/students/import')
-      .set(auth(adminToken))
-      .attach('file', workbookBuffer, {
-        filename: 'attendance-workflow-students.xlsx',
-        contentType: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
-      })
-      .expect(201);
-    expect(importResult.body).toMatchObject({ imported: 2, skipped: 0 });
-
-    const [studentA, studentB] = await Promise.all([
-      studentRepo.findOneByOrFail({ phone: '13800000001' }),
-      studentRepo.findOneByOrFail({ phone: '13800000002' }),
-    ]);
-    await mappingRepo.save([
-      mappingRepo.create({ dingUserId: STUDENT_A_DING_ID, studentId: studentA.id }),
-      mappingRepo.create({ dingUserId: STUDENT_B_DING_ID, studentId: studentB.id }),
-    ]);
-
-    const classResult = await request(app.getHttpServer())
-      .post('/api/classes')
-      .set(auth(adminToken))
-      .send({
-        name: '集成考勤班',
-        code: 'ATTENDANCE-INTEGRATION',
-        classType: 'culture',
-        status: 'active',
-        startDate: LESSON_DATE,
-        endDate: LESSON_DATE,
-      })
-      .expect(201);
-    const classId = classResult.body.id;
-
-    await request(app.getHttpServer())
-      .post(`/api/classes/${classId}/students`)
-      .set(auth(adminToken))
-      .send({ studentIds: [studentA.id, studentB.id] })
-      .expect(201)
-      .expect(({ body }) => expect(body).toMatchObject({ added: 2, skipped: 0 }));
-
-    await request(app.getHttpServer())
-      .post(`/api/classes/${classId}/teachers`)
-      .set(auth(adminToken))
-      .send({ userId: teacherId, roleType: 'subject_teacher', subject: '语文' })
-      .expect(201);
-
-    const classroomResult = await request(app.getHttpServer())
-      .post('/api/classrooms')
-      .set(auth(adminToken))
-      .send({ name: '集成测试教室', building: '测试楼', floor: 1, capacity: 30, roomType: '小' })
-      .expect(201);
-
-    const scheduleResult = await request(app.getHttpServer())
-      .post('/api/class-schedules')
-      .set(auth(adminToken))
-      .send({
-        classId,
-        classroomId: classroomResult.body.id,
-        weekDay: chinaWeekDay(LESSON_DATE),
-        startTime: '00:00',
-        endTime: '23:59',
-        attendanceAdvanceMinutes: 0,
-        startDate: LESSON_DATE,
-        endDate: LESSON_DATE,
-        subject: '语文',
-        teacherId,
-        scheduleType: 'INTERNAL',
-      })
-      .expect(201);
-    const scheduleId = scheduleResult.body.id;
-
-    const initialPull = await request(app.getHttpServer())
-      .post(`/api/attendance-lessons/schedules/${scheduleId}/pull`)
-      .set(auth(teacherToken))
-      .send({ date: LESSON_DATE })
-      .expect(201);
-    expect(initialPull.body.records).toHaveLength(2);
-    expect(initialPull.body.records.map((record: AttendanceRecord) => record.status)).toEqual([
-      'pending',
-      'pending',
-    ]);
-
-    const studentARecord = initialPull.body.records.find(
-      (record: AttendanceRecord) => record.studentId === studentA.id,
-    );
-    await request(app.getHttpServer())
-      .put(`/api/attendance-records/${studentARecord.id}`)
-      .set(auth(teacherToken))
-      .send({ status: 'absent', remark: '教师本地覆盖' })
-      .expect(200)
-      .expect(({ body }) => expect(body).toMatchObject({ status: 'absent', source: 'manual' }));
-
-    mockedPunches = [
-      attendanceResult(STUDENT_A_DING_ID, 'integration-check-a', `${LESSON_DATE}T01:00:00.000Z`),
-      attendanceResult(STUDENT_B_DING_ID, 'integration-check-b', `${LESSON_DATE}T01:05:00.000Z`),
-    ];
-
-    const refreshed = await request(app.getHttpServer())
-      .post(`/api/attendance-lessons/schedules/${scheduleId}/pull`)
-      .set(auth(teacherToken))
-      .send({ date: LESSON_DATE })
-      .expect(201);
-    expect(refreshed.body.records).toHaveLength(2);
-    expect(
-      refreshed.body.records.find((record: AttendanceRecord) => record.studentId === studentA.id),
-    ).toMatchObject({ status: 'absent', source: 'manual', remark: '教师本地覆盖' });
-    expect(
-      refreshed.body.records.find((record: AttendanceRecord) => record.studentId === studentB.id),
-    ).toMatchObject({ status: 'present', source: 'dingtalk', punchSource: 'ATM' });
-
-    const teacherRecords = await request(app.getHttpServer())
-      .get(
-        `/api/attendance-records?classId=${classId}&dateFrom=${LESSON_DATE}&dateTo=${LESSON_DATE}`,
-      )
-      .set(auth(teacherToken))
-      .expect(200);
-    expect(teacherRecords.body.list).toHaveLength(2);
-    const teacherView: Array<Pick<AttendanceRecord, 'studentId' | 'status' | 'source'>> =
-      teacherRecords.body.list
-        .map((record: AttendanceRecord) => ({
-          studentId: record.studentId,
-          status: record.status,
-          source: record.source,
-        }))
-        .sort((left, right) => left.studentId - right.studentId);
-    expect(teacherView).toEqual([
-      { studentId: studentA.id, status: 'absent', source: 'manual' },
-      { studentId: studentB.id, status: 'present', source: 'dingtalk' },
-    ]);
-
-    const adminRecords = await request(app.getHttpServer())
-      .get(
-        `/api/attendance-records?classId=${classId}&dateFrom=${LESSON_DATE}&dateTo=${LESSON_DATE}`,
-      )
-      .set(auth(adminToken))
-      .expect(200);
-    expect(adminRecords.body.list).toHaveLength(2);
-    expect(
-      adminRecords.body.list
-        .map((record: AttendanceRecord) => ({
-          studentId: record.studentId,
-          status: record.status,
-          source: record.source,
-        }))
-        .sort(
-          (left: Pick<AttendanceRecord, 'studentId'>, right: Pick<AttendanceRecord, 'studentId'>) =>
-            left.studentId - right.studentId,
-        ),
-    ).toEqual(teacherView);
-
-    const unassignedClass = await request(app.getHttpServer())
-      .post('/api/classes')
-      .set(auth(adminToken))
-      .send({
-        name: '未分配教师班级',
-        code: 'UNASSIGNED-INTEGRATION',
-        classType: 'culture',
-        status: 'active',
-      })
-      .expect(201);
-    await request(app.getHttpServer())
-      .get(`/api/attendance-records?classId=${unassignedClass.body.id}`)
-      .set(auth(teacherToken))
-      .expect(400);
-
-    const persisted = await attendanceRepo.find({
-      where: { classId },
-      order: { studentId: 'ASC' },
-    });
-    expect(persisted).toHaveLength(2);
-    expect(persisted).toEqual([
-      expect.objectContaining({ studentId: studentA.id, status: 'absent', source: 'manual' }),
-      expect.objectContaining({ studentId: studentB.id, status: 'present', source: 'dingtalk' }),
-    ]);
-  });
-});
diff --git a/apps/server/src/attendance/attendance.lesson-session.spec.ts b/apps/server/src/attendance/attendance.lesson-session.spec.ts
index ecc8887..4509b9d 100644
--- a/apps/server/src/attendance/attendance.lesson-session.spec.ts
+++ b/apps/server/src/attendance/attendance.lesson-session.spec.ts
@@ -577,9 +577,9 @@ describe('AttendanceService \u2014 DingTalk course attendance', () => {
       });
     // Simulate unique constraint on save
     sessionRepo.save.mockRejectedValueOnce(
-      Object.assign(new Error('UNIQUE constraint failed'), {
-        code: 'SQLITE_CONSTRAINT',
-        errno: undefined,
+      Object.assign(new Error('Duplicate entry'), {
+        code: 'ER_DUP_ENTRY',
+        errno: 1062,
       }),
     );
     classStudentRepo.find.mockResolvedValue([{ studentId: 1, student: { id: 1, name: '张三' } }]);
diff --git a/apps/server/src/database/attendance-fk-restrict.spec.ts b/apps/server/src/database/attendance-fk-restrict.spec.ts
deleted file mode 100644
index 81f915d..0000000
--- a/apps/server/src/database/attendance-fk-restrict.spec.ts
+++ /dev/null
@@ -1,380 +0,0 @@
-import Database from 'better-sqlite3';
-type SqliteDB = InstanceType<typeof Database>;
-
-/**
- * Real SQLite foreign-key constraint tests.
- *
- * These tests use the `better-sqlite3` driver directly (in-memory) to verify
- * that ON DELETE RESTRICT is enforced at the database level, not just in
- * application-layer guards.
- */
-describe('attendance_sessions FK RESTRICT — real SQLite', () => {
-  let db: SqliteDB;
-
-  function createSchema(): void {
-    db.exec('PRAGMA foreign_keys = ON');
-    db.exec(`
-      CREATE TABLE IF NOT EXISTS classes (
-        id INTEGER PRIMARY KEY AUTOINCREMENT,
-        name TEXT NOT NULL,
-        is_archived INTEGER DEFAULT 0
-      )
-    `);
-    db.exec(`
-      CREATE TABLE IF NOT EXISTS class_schedule (
-        id INTEGER PRIMARY KEY AUTOINCREMENT,
-        class_id INTEGER,
-        week_day INTEGER NOT NULL
-      )
-    `);
-    db.exec(`
-      CREATE TABLE IF NOT EXISTS attendance_sessions (
-        id INTEGER PRIMARY KEY AUTOINCREMENT,
-        schedule_id INTEGER NOT NULL,
-        class_id INTEGER NOT NULL,
-        lesson_date DATE NOT NULL,
-        status TEXT DEFAULT 'in_progress',
-        FOREIGN KEY (schedule_id) REFERENCES class_schedule(id) ON DELETE RESTRICT,
-        FOREIGN KEY (class_id) REFERENCES classes(id) ON DELETE RESTRICT
-      )
-    `);
-  }
-
-  beforeEach(() => {
-    db = new Database(':memory:');
-    createSchema();
-  });
-
-  afterEach(() => {
-    db.close();
-  });
-
-  it('blocks class deletion when attendance sessions reference it', () => {
-    db.exec("INSERT INTO classes (id, name) VALUES (1, 'Test Class')");
-    db.exec("INSERT INTO class_schedule (id, class_id, week_day) VALUES (1, 1, 1)");
-    db.exec(
-      "INSERT INTO attendance_sessions (id, schedule_id, class_id, lesson_date) VALUES (1, 1, 1, '2026-01-01')",
-    );
-
-    expect(() => {
-      db.exec('DELETE FROM classes WHERE id = 1');
-    }).toThrow();
-  });
-
-  it('allows class deletion when no attendance sessions reference it', () => {
-    db.exec("INSERT INTO classes (id, name) VALUES (1, 'Test Class')");
-
-    expect(() => {
-      db.exec('DELETE FROM classes WHERE id = 1');
-    }).not.toThrow();
-
-    const remaining = db.prepare('SELECT COUNT(*) as cnt FROM classes').get() as {
-      cnt: number;
-    };
-    expect(remaining.cnt).toBe(0);
-  });
-
-  it('blocks schedule deletion when attendance sessions reference it', () => {
-    db.exec("INSERT INTO classes (id, name) VALUES (1, 'Test Class')");
-    db.exec("INSERT INTO class_schedule (id, class_id, week_day) VALUES (1, 1, 1)");
-    db.exec(
-      "INSERT INTO attendance_sessions (id, schedule_id, class_id, lesson_date) VALUES (1, 1, 1, '2026-01-01')",
-    );
-
-    expect(() => {
-      db.exec('DELETE FROM class_schedule WHERE id = 1');
-    }).toThrow();
-  });
-
-  it('PRAGMA foreign_key_list confirms both FKs are present', () => {
-    // Use raw SQL PRAGMA to avoid better-sqlite3 pragma API quirks
-    const rows = db.prepare("PRAGMA foreign_key_list('attendance_sessions')").all() as Array<{
-      id: number;
-      seq: number;
-      table: string;
-      from: string;
-      to: string;
-      on_update: string;
-      on_delete: string;
-      match: string;
-    }>;
-
-    expect(rows.length).toBe(2);
-
-    const scheduleFk = rows.find((fk) => fk.from === 'schedule_id');
-    expect(scheduleFk).toBeDefined();
-    expect(scheduleFk!.table).toBe('class_schedule');
-    expect(scheduleFk!.on_delete).toBe('RESTRICT');
-
-    const classFk = rows.find((fk) => fk.from === 'class_id');
-    expect(classFk).toBeDefined();
-    expect(classFk!.table).toBe('classes');
-    expect(classFk!.on_delete).toBe('RESTRICT');
-  });
-
-  it('FK pragma respects ON DELETE RESTRICT for class_id — data survives failed delete', () => {
-    db.exec("INSERT INTO classes (id, name) VALUES (1, 'Test Class')");
-    db.exec("INSERT INTO class_schedule (id, class_id, week_day) VALUES (1, 1, 1)");
-    db.exec(
-      "INSERT INTO attendance_sessions (id, schedule_id, class_id, lesson_date) VALUES (1, 1, 1, '2026-01-01')",
-    );
-
-    // Verify the session exists
-    const session = db
-      .prepare('SELECT * FROM attendance_sessions WHERE class_id = 1')
-      .get() as Record<string, unknown>;
-    expect(session).toBeDefined();
-
-    // Delete should fail
-    expect(() => db.exec('DELETE FROM classes WHERE id = 1')).toThrow();
-
-    // Session should still exist after failed delete
-    const after = db
-      .prepare('SELECT COUNT(*) as cnt FROM attendance_sessions WHERE class_id = 1')
-      .get() as { cnt: number };
-    expect(after.cnt).toBe(1);
-  });
-});
-
-/**
- * Integration test: simulate the protectAttendanceHistory SQLite migration.
- *
- * Creates tables WITHOUT foreign keys (pre-migration state), inserts parent
- * session and child attendance_record, runs the table-rebuild migration
- * (PRAGMA foreign_keys=OFF, rebuild both tables, PRAGMA foreign_keys=ON,
- * foreign_key_check), then verifies:
- *  - attendance_record.attendance_session_id is preserved
- *  - RESTRICT still blocks class/schedule deletion
- */
-describe('protectAttendanceHistory SQLite migration — integration', () => {
-  let db: SqliteDB;
-
-  function createPreMigrationSchema(): void {
-    // Schema WITHOUT foreign keys on attendance_sessions (pre-migration)
-    db.exec('PRAGMA foreign_keys = ON');
-    db.exec(`
-      CREATE TABLE IF NOT EXISTS classes (
-        id INTEGER PRIMARY KEY AUTOINCREMENT,
-        name TEXT NOT NULL,
-        is_archived INTEGER DEFAULT 0
-      )
-    `);
-    db.exec(`
-      CREATE TABLE IF NOT EXISTS class_schedule (
-        id INTEGER PRIMARY KEY AUTOINCREMENT,
-        class_id INTEGER,
-        week_day INTEGER NOT NULL
-      )
-    `);
-    // attendance_sessions WITHOUT foreign keys
-    db.exec(`
-      CREATE TABLE IF NOT EXISTS attendance_sessions (
-        id INTEGER PRIMARY KEY AUTOINCREMENT,
-        schedule_id INTEGER NOT NULL,
-        class_id INTEGER NOT NULL,
-        lesson_date DATE NOT NULL,
-        status TEXT DEFAULT 'in_progress',
-        started_by INTEGER,
-        started_at DATETIME,
-        completed_by INTEGER,
-        completed_at DATETIME,
-        created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-        updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
-      )
-    `);
-    // Legacy columns came first; course-attendance columns were appended later.
-    db.exec(`
-      CREATE TABLE IF NOT EXISTS attendance_records (
-        id INTEGER PRIMARY KEY AUTOINCREMENT,
-        student_id INTEGER NOT NULL,
-        class_id INTEGER,
-        attendance_date DATE NOT NULL,
-        session VARCHAR(20) NOT NULL,
-        status VARCHAR(20) NOT NULL,
-        remark VARCHAR(200),
-        source VARCHAR(20) DEFAULT 'manual',
-        created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-        updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-        schedule_id INTEGER,
-        attendance_session_id INTEGER
-      )
-    `);
-  }
-
-  function runMigration(): void {
-    // Step 1: PRAGMA foreign_keys = OFF outside transaction
-    db.exec('PRAGMA foreign_keys = OFF');
-    try {
-      db.exec('BEGIN');
-      try {
-        // Rebuild attendance_sessions with FKs
-        db.exec(`
-          CREATE TABLE attendance_sessions_new (
-            id INTEGER PRIMARY KEY AUTOINCREMENT,
-            schedule_id INTEGER NOT NULL,
-            class_id INTEGER NOT NULL,
-            lesson_date DATE NOT NULL,
-            status VARCHAR(20) NOT NULL DEFAULT 'in_progress',
-            started_by INTEGER,
-            started_at DATETIME,
-            completed_by INTEGER,
-            completed_at DATETIME,
-            created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-            updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-            FOREIGN KEY (schedule_id) REFERENCES class_schedule(id) ON DELETE RESTRICT,
-            FOREIGN KEY (class_id) REFERENCES classes(id) ON DELETE RESTRICT
-          )
-        `);
-        db.exec(
-          'INSERT INTO attendance_sessions_new SELECT * FROM attendance_sessions',
-        );
-        db.exec('DROP TABLE attendance_sessions');
-        db.exec(
-          'ALTER TABLE attendance_sessions_new RENAME TO attendance_sessions',
-        );
-        db.exec(
-          'CREATE UNIQUE INDEX IF NOT EXISTS uq_attendance_session_schedule_date ON attendance_sessions(schedule_id, lesson_date)',
-        );
-
-        // Rebuild attendance_records with FK on attendance_session_id
-        const recordsFk = db
-          .prepare("PRAGMA foreign_key_list('attendance_records')")
-          .all() as Array<{ from: string }>;
-        const hasSessionFk = recordsFk.some((r) => r.from === 'attendance_session_id');
-        if (!hasSessionFk) {
-          db.exec(`
-            CREATE TABLE attendance_records_new (
-              id INTEGER PRIMARY KEY AUTOINCREMENT,
-              student_id INTEGER NOT NULL,
-              class_id INTEGER,
-              schedule_id INTEGER,
-              attendance_session_id INTEGER,
-              attendance_date DATE NOT NULL,
-              session VARCHAR(20) NOT NULL,
-              status VARCHAR(20) NOT NULL,
-              remark VARCHAR(200),
-              source VARCHAR(20) DEFAULT 'manual',
-              created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-              updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-              FOREIGN KEY (attendance_session_id) REFERENCES attendance_sessions(id) ON DELETE SET NULL
-            )
-          `);
-          db.exec(`
-            INSERT INTO attendance_records_new (
-              id, student_id, class_id, schedule_id, attendance_session_id,
-              attendance_date, session, status, remark, source, created_at, updated_at
-            )
-            SELECT
-              id, student_id, class_id, schedule_id, attendance_session_id,
-              attendance_date, session, status, remark, source, created_at, updated_at
-            FROM attendance_records
-          `);
-          db.exec('DROP TABLE attendance_records');
-          db.exec(
-            'ALTER TABLE attendance_records_new RENAME TO attendance_records',
-          );
-          db.exec(
-            'CREATE UNIQUE INDEX IF NOT EXISTS uq_attendance_session_student ON attendance_records(attendance_session_id, student_id)',
-          );
-        }
-
-        db.exec('COMMIT');
-      } catch (err) {
-        db.exec('ROLLBACK');
-        throw err;
-      }
-    } finally {
-      db.exec('PRAGMA foreign_keys = ON');
-    }
-
-    // Run foreign_key_check — should be clean
-    const checkRows = db.prepare('PRAGMA foreign_key_check').all();
-    if (checkRows.length > 0) {
-      throw new Error(
-        `外键一致性检查失败: ${checkRows.length} 行违反外键约束`,
-      );
-    }
-  }
-
-  beforeEach(() => {
-    db = new Database(':memory:');
-    createPreMigrationSchema();
-  });
-
-  afterEach(() => {
-    db.close();
-  });
-
-  it('preserves attendance_record.session_id after migration', () => {
-    db.exec("INSERT INTO classes (id, name) VALUES (1, 'Test Class')");
-    db.exec("INSERT INTO class_schedule (id, class_id, week_day) VALUES (1, 1, 1)");
-    db.exec(
-      "INSERT INTO attendance_sessions (id, schedule_id, class_id, lesson_date) VALUES (1, 1, 1, '2026-01-01')",
-    );
-    db.exec(
-      "INSERT INTO attendance_records (id, student_id, class_id, attendance_session_id, attendance_date, session, status) VALUES (1, 1, 1, 1, '2026-01-01', 'morning', 'present')",
-    );
-
-    // Verify pre-migration state
-    const preSessionFk = db
-      .prepare("PRAGMA foreign_key_list('attendance_sessions')")
-      .all();
-    expect(preSessionFk.length).toBe(0);
-
-    const preRecordsFk = db
-      .prepare("PRAGMA foreign_key_list('attendance_records')")
-      .all();
-    expect(preRecordsFk.length).toBe(0);
-
-    // Run migration
-    runMigration();
-
-    // Verify attendance_record still has correct attendance_session_id
-    const record = db
-      .prepare('SELECT * FROM attendance_records WHERE id = 1')
-      .get() as Record<string, unknown>;
-    expect(record).toBeDefined();
-    expect(record.attendance_session_id).toBe(1);
-    expect(record.attendance_date).toBe('2026-01-01');
-    expect(record.session).toBe('morning');
-    expect(record.status).toBe('present');
-
-    // Verify FKs now exist on both tables
-    const postSessionFk = db
-      .prepare("PRAGMA foreign_key_list('attendance_sessions')")
-      .all();
-    expect(postSessionFk.length).toBe(2);
-
-    const postRecordsFk = db
-      .prepare("PRAGMA foreign_key_list('attendance_records')")
-      .all() as Array<{ from: string; table: string; on_delete: string }>;
-    const sessionFk = postRecordsFk.find((r) => r.from === 'attendance_session_id');
-    expect(sessionFk).toBeDefined();
-    expect(sessionFk!.table).toBe('attendance_sessions');
-    expect(sessionFk!.on_delete).toBe('SET NULL');
-
-    // RESTRICT still blocks class/schedule deletion
-    expect(() => {
-      db.exec('DELETE FROM classes WHERE id = 1');
-    }).toThrow();
-    expect(() => {
-      db.exec('DELETE FROM class_schedule WHERE id = 1');
-    }).toThrow();
-
-    // Verify data survived the failed deletes
-    const sessionAfter = db
-      .prepare('SELECT COUNT(*) as cnt FROM attendance_sessions WHERE id = 1')
-      .get() as { cnt: number };
-    expect(sessionAfter.cnt).toBe(1);
-
-    const recordAfter = db
-      .prepare('SELECT COUNT(*) as cnt FROM attendance_records WHERE id = 1')
-      .get() as { cnt: number };
-    expect(recordAfter.cnt).toBe(1);
-
-    const classAfter = db
-      .prepare('SELECT COUNT(*) as cnt FROM classes WHERE id = 1')
-      .get() as { cnt: number };
-    expect(classAfter.cnt).toBe(1);
-  });
-});
diff --git a/apps/server/src/database/database-migrations.ai.ts b/apps/server/src/database/database-migrations.ai.ts
index 77d77a8..d49a403 100644
--- a/apps/server/src/database/database-migrations.ai.ts
+++ b/apps/server/src/database/database-migrations.ai.ts
@@ -8,14 +8,11 @@ export async function ensureAiConfigTable(
 ): Promise<void> {
   await withQueryRunner(dataSource, async (runner) => {
     const tables = await runner.getTables(['ai_config']);
-    const isMySQL = dataSource.options.type === 'mysql';
 
     if (tables.length === 0) {
-      const pkDef = isMySQL
-        ? 'id INTEGER PRIMARY KEY AUTO_INCREMENT'
-        : 'id INTEGER PRIMARY KEY AUTOINCREMENT';
-      const boolType = isMySQL ? 'TINYINT(1)' : 'BOOLEAN';
-      const datetimeFn = isMySQL ? 'CURRENT_TIMESTAMP' : 'CURRENT_TIMESTAMP';
+      const pkDef = 'id INTEGER PRIMARY KEY AUTO_INCREMENT';
+      const boolType = 'TINYINT(1)';
+      const datetimeFn = 'CURRENT_TIMESTAMP';
 
       await runner.query(`
           CREATE TABLE ai_config (
@@ -38,18 +35,12 @@ export async function ensureAiConfigTable(
           )
         `);
 
-      if (isMySQL) {
-        try {
-          await runner.query(
-            'CREATE UNIQUE INDEX uq_ai_config_singleton ON ai_config(singleton_key)',
-          );
-        } catch {
-          // Index may already exist; MySQL has no IF NOT EXISTS for indexes
-        }
-      } else {
+      try {
         await runner.query(
-          'CREATE UNIQUE INDEX IF NOT EXISTS uq_ai_config_singleton ON ai_config(singleton_key)',
+          'CREATE UNIQUE INDEX uq_ai_config_singleton ON ai_config(singleton_key)',
         );
+      } catch {
+        // Index may already exist; MySQL has no IF NOT EXISTS for indexes
       }
 
       logger.log('已创建 ai_config 表');
@@ -67,10 +58,10 @@ export async function ensureAiConfigTable(
         { name: 'api_key_auth_tag', def: 'VARCHAR(50)' },
         { name: 'key_last4', def: 'VARCHAR(4)' },
         { name: 'default_model', def: 'VARCHAR(100)' },
-        { name: 'enabled', def: isMySQL ? 'TINYINT(1) DEFAULT 0' : 'BOOLEAN DEFAULT 0' },
+        { name: 'enabled', def: 'TINYINT(1) DEFAULT 0' },
         { name: 'timeout_ms', def: 'INT DEFAULT 30000' },
         { name: 'reasoning_effort', def: 'VARCHAR(20)' },
-        { name: 'verified', def: isMySQL ? 'TINYINT(1) DEFAULT 0' : 'BOOLEAN DEFAULT 0' },
+        { name: 'verified', def: 'TINYINT(1) DEFAULT 0' },
         { name: 'last_tested_at', def: 'DATETIME' },
         { name: 'last_test_latency_ms', def: 'INT' },
         { name: 'created_at', def: 'DATETIME' },
diff --git a/apps/server/src/database/database-migrations.attendance.ts b/apps/server/src/database/database-migrations.attendance.ts
index f76a7b2..b68f9fd 100644
--- a/apps/server/src/database/database-migrations.attendance.ts
+++ b/apps/server/src/database/database-migrations.attendance.ts
@@ -33,13 +33,11 @@ export async function ensureCourseAttendanceSchema(
       'attendance_sessions',
     ]);
     const tableNames = new Set(tables.map((table) => table.name));
-    const isMySQL = dataSource.options.type === 'mysql';
 
     if (!tableNames.has('attendance_sessions')) {
-      const pkDef = isMySQL
-        ? 'id INTEGER PRIMARY KEY AUTO_INCREMENT'
-        : 'id INTEGER PRIMARY KEY AUTOINCREMENT';
-      await runner.query(attendanceSessionsDdl('attendance_sessions', pkDef));
+      await runner.query(
+        attendanceSessionsDdl('attendance_sessions', 'id INTEGER PRIMARY KEY AUTO_INCREMENT'),
+      );
     }
 
     if (tableNames.has('class_schedule')) {
@@ -72,14 +70,10 @@ export async function ensureCourseAttendanceSchema(
       }
     };
     await createIndex(
-      isMySQL
-        ? 'CREATE UNIQUE INDEX uq_attendance_session_schedule_date ON attendance_sessions(schedule_id, lesson_date)'
-        : 'CREATE UNIQUE INDEX IF NOT EXISTS uq_attendance_session_schedule_date ON attendance_sessions(schedule_id, lesson_date)',
+      'CREATE UNIQUE INDEX uq_attendance_session_schedule_date ON attendance_sessions(schedule_id, lesson_date)',
     );
     await createIndex(
-      isMySQL
-        ? 'CREATE UNIQUE INDEX uq_attendance_session_student ON attendance_records(attendance_session_id, student_id)'
-        : 'CREATE UNIQUE INDEX IF NOT EXISTS uq_attendance_session_student ON attendance_records(attendance_session_id, student_id)',
+      'CREATE UNIQUE INDEX uq_attendance_session_student ON attendance_records(attendance_session_id, student_id)',
     );
   });
 }
@@ -92,12 +86,7 @@ export async function protectAttendanceHistory(
     const tables = await runner.getTables(['attendance_sessions']);
     if (tables.length === 0) return;
 
-    const isMySQL = dataSource.options.type === 'mysql';
-    if (isMySQL) {
-      await migrateMySQLAttendanceFKs(runner, logger);
-    } else {
-      await migrateSQLiteAttendanceFKs(runner, logger);
-    }
+    await migrateMySQLAttendanceFKs(runner, logger);
   });
 }
 
@@ -164,97 +153,3 @@ export async function migrateMySQLAttendanceFKs(
     logger.log(`已添加考勤场次删除保护约束: ${c.name}`);
   }
 }
-
-export async function migrateSQLiteAttendanceFKs(
-  runner: QueryRunner,
-  logger: Logger,
-): Promise<void> {
-  // SQLite cannot ALTER TABLE to add foreign keys.
-  // Rebuild the table inside a transaction: create a new table with FK constraints,
-  // copy all rows, drop old, rename new, then recreate indexes.
-  const fkRows: Array<{ id: number }> = await runner.query(
-    "PRAGMA foreign_key_list('attendance_sessions')",
-  );
-  if (fkRows.length > 0) return; // FKs already present
-
-  logger.log('正在重建 attendance_sessions 表以添加外键保护…');
-
-  // PRAGMA foreign_keys=OFF must be issued outside the transaction
-  await runner.query('PRAGMA foreign_keys = OFF');
-  try {
-    await runner.query('BEGIN');
-    try {
-      await runner.query(attendanceSessionsDdl('attendance_sessions_new', 'id INTEGER PRIMARY KEY AUTOINCREMENT'));
-      await runner.query(`
-          INSERT INTO attendance_sessions_new (
-            id, schedule_id, class_id, lesson_date, status,
-            started_by, started_at, completed_by, completed_at, created_at, updated_at
-          )
-          SELECT
-            id, schedule_id, class_id, lesson_date, status,
-            started_by, started_at, completed_by, completed_at, created_at, updated_at
-          FROM attendance_sessions
-        `);
-      await runner.query('DROP TABLE attendance_sessions');
-      await runner.query('ALTER TABLE attendance_sessions_new RENAME TO attendance_sessions');
-      await runner.query(
-        'CREATE UNIQUE INDEX IF NOT EXISTS uq_attendance_session_schedule_date ON attendance_sessions(schedule_id, lesson_date)',
-      );
-
-      // Rebuild attendance_records to add/protect FK on attendance_session_id
-      const recordsFk = await runner.query("PRAGMA foreign_key_list('attendance_records')");
-      const hasSessionFk = recordsFk.some(
-        (r: { from: string }) => r.from === 'attendance_session_id',
-      );
-      if (!hasSessionFk) {
-        await runner.query(`
-            CREATE TABLE attendance_records_new (
-              id INTEGER PRIMARY KEY AUTOINCREMENT,
-              student_id INTEGER NOT NULL,
-              class_id INTEGER,
-              schedule_id INTEGER,
-              attendance_session_id INTEGER,
-              attendance_date DATE NOT NULL,
-              session VARCHAR(20) NOT NULL,
-              status VARCHAR(20) NOT NULL,
-              remark VARCHAR(200),
-              source VARCHAR(20) DEFAULT 'manual',
-              created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-              updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-              FOREIGN KEY (attendance_session_id) REFERENCES attendance_sessions(id) ON DELETE SET NULL
-            )
-          `);
-        await runner.query(`
-            INSERT INTO attendance_records_new (
-              id, student_id, class_id, schedule_id, attendance_session_id,
-              attendance_date, session, status, remark, source, created_at, updated_at
-            )
-            SELECT
-              id, student_id, class_id, schedule_id, attendance_session_id,
-              attendance_date, session, status, remark, source, created_at, updated_at
-            FROM attendance_records
-          `);
-        await runner.query('DROP TABLE attendance_records');
-        await runner.query('ALTER TABLE attendance_records_new RENAME TO attendance_records');
-        await runner.query(
-          'CREATE UNIQUE INDEX IF NOT EXISTS uq_attendance_session_student ON attendance_records(attendance_session_id, student_id)',
-        );
-      }
-
-      // Verify foreign key integrity BEFORE committing the transaction.
-      // If violations exist, the transaction rolls back and old tables are preserved.
-      const checkRows = await runner.query('PRAGMA foreign_key_check');
-      if (checkRows.length > 0) {
-        throw new Error(`外键一致性检查失败: ${checkRows.length} 行违反外键约束`);
-      }
-
-      await runner.query('COMMIT');
-      logger.log('attendance_sessions 表外键保护重建完成');
-    } catch (err) {
-      await runner.query('ROLLBACK');
-      throw err;
-    }
-  } finally {
-    await runner.query('PRAGMA foreign_keys = ON');
-  }
-}
diff --git a/apps/server/src/database/database-migrations.backfill.ts b/apps/server/src/database/database-migrations.backfill.ts
index d5fbf67..be47e00 100644
--- a/apps/server/src/database/database-migrations.backfill.ts
+++ b/apps/server/src/database/database-migrations.backfill.ts
@@ -124,7 +124,6 @@ export async function normalizeClassDates(
   dataSource: DataSource,
   logger: Logger,
 ): Promise<void> {
-  const driver = dataSource.options.type;
   let columns: Array<'start_date' | 'end_date'> = ['start_date', 'end_date'];
 
   await withQueryRunner(dataSource, async (runner) => {
@@ -135,27 +134,21 @@ export async function normalizeClassDates(
     // This cleanup is only for legacy schemas that stored dates as strings;
     // comparing a native DATE column with '' raises ER_TRUNCATED_WRONG_VALUE
     // in strict SQL mode.
-    if (driver === 'mysql') {
-      columns = columns.filter((columnName) => {
-        const column = table.columns.find((item) => item.name === columnName);
-        const type = String(column?.type ?? '').toLowerCase();
-        return !['date', 'datetime', 'timestamp'].includes(type);
-      });
-      if (columns.length === 0) return;
-    }
+    columns = columns.filter((columnName) => {
+      const column = table.columns.find((item) => item.name === columnName);
+      const type = String(column?.type ?? '').toLowerCase();
+      return !['date', 'datetime', 'timestamp'].includes(type);
+    });
+    if (columns.length === 0) return;
   });
 
-  const columnText = (column: string) =>
-    driver === 'mysql' ? `CAST(${column} AS CHAR)` : column;
-  const firstTenChars = (column: string) =>
-    driver === 'mysql'
-      ? `NULLIF(LEFT(${columnText(column)}, 10), '')`
-      : `NULLIF(substr(${column}, 1, 10), '')`;
+  const columnText = (column: string) => `CAST(${column} AS CHAR)`;
+  const firstTenChars = (column: string) => `NULLIF(LEFT(${columnText(column)}, 10), '')`;
   const normalizedDate = (column: string) => `CASE
             WHEN ${column} IS NULL THEN NULL
             ELSE ${firstTenChars(column)}
           END`;
-  const lengthFunction = driver === 'mysql' ? 'CHAR_LENGTH' : 'length';
+  const lengthFunction = 'CHAR_LENGTH';
   const needsNormalization = (column: string) => `(
             ${column} IS NOT NULL
             AND (${columnText(column)} = '' OR ${lengthFunction}(${columnText(column)}) > 10)
diff --git a/apps/server/src/database/database-migrations.class-student.spec.ts b/apps/server/src/database/database-migrations.class-student.spec.ts
index 6088762..b07946f 100644
--- a/apps/server/src/database/database-migrations.class-student.spec.ts
+++ b/apps/server/src/database/database-migrations.class-student.spec.ts
@@ -22,7 +22,7 @@ async function createService(runner: ReturnType<typeof createRunner>) {
       {
         provide: getDataSourceToken(),
         useValue: {
-          options: { type: 'better-sqlite3' },
+          options: { type: 'mysql' },
           createQueryRunner: jest.fn().mockReturnValue(runner),
         },
       },
diff --git a/apps/server/src/database/database-migrations.classroom-status.spec.ts b/apps/server/src/database/database-migrations.classroom-status.spec.ts
index aaf079e..3702eaf 100644
--- a/apps/server/src/database/database-migrations.classroom-status.spec.ts
+++ b/apps/server/src/database/database-migrations.classroom-status.spec.ts
@@ -16,7 +16,7 @@ describe('DatabaseMigrationsService — classroom status normalization', () => {
         {
           provide: getDataSourceToken(),
           useValue: {
-            options: { type: 'better-sqlite3' },
+            options: { type: 'mysql' },
             createQueryRunner: jest.fn().mockReturnValue(runner),
           },
         },
diff --git a/apps/server/src/database/database-migrations.deposit-refund.spec.ts b/apps/server/src/database/database-migrations.deposit-refund.spec.ts
index 1b1ac7c..376de04 100644
--- a/apps/server/src/database/database-migrations.deposit-refund.spec.ts
+++ b/apps/server/src/database/database-migrations.deposit-refund.spec.ts
@@ -24,7 +24,7 @@ async function createService(runner: ReturnType<typeof createRunner>) {
       {
         provide: getDataSourceToken(),
         useValue: {
-          options: { type: 'better-sqlite3' },
+          options: { type: 'mysql' },
           createQueryRunner: jest.fn().mockReturnValue(runner),
         },
       },
diff --git a/apps/server/src/database/database-migrations.room-gender.spec.ts b/apps/server/src/database/database-migrations.room-gender.spec.ts
index 3728e3c..12fad00 100644
--- a/apps/server/src/database/database-migrations.room-gender.spec.ts
+++ b/apps/server/src/database/database-migrations.room-gender.spec.ts
@@ -20,7 +20,7 @@ describe('DatabaseMigrationsService — room gender cleanup', () => {
         {
           provide: getDataSourceToken(),
           useValue: {
-            options: { type: 'better-sqlite3' },
+            options: { type: 'mysql' },
             createQueryRunner: jest.fn().mockReturnValue(runner),
           },
         },
diff --git a/apps/server/src/database/database-migrations.schema.ts b/apps/server/src/database/database-migrations.schema.ts
index fd8d271..09e9929 100644
--- a/apps/server/src/database/database-migrations.schema.ts
+++ b/apps/server/src/database/database-migrations.schema.ts
@@ -38,8 +38,7 @@ export async function ensureAttendanceDevicesSchema(
   dataSource: DataSource,
 ): Promise<void> {
   await withQueryRunner(dataSource, async (runner) => {
-    const isMySQL = dataSource.options.type === 'mysql';
-    const pk = isMySQL ? 'INTEGER PRIMARY KEY AUTO_INCREMENT' : 'INTEGER PRIMARY KEY AUTOINCREMENT';
+    const pk = 'INTEGER PRIMARY KEY AUTO_INCREMENT';
     await runner.query(`CREATE TABLE IF NOT EXISTS attendance_devices (
         id ${pk},
         device_sn VARCHAR(100) NOT NULL,
@@ -77,15 +76,11 @@ export async function ensureAttendanceDevicesSchema(
     const uniqueSn = refreshed?.indices.some((index) => index.columnNames.length === 1 && index.columnNames[0] === 'device_sn' && index.isUnique);
     if (!uniqueSn) {
       await createIndex(
-        isMySQL
-          ? 'CREATE UNIQUE INDEX idx_attendance_devices_device_sn ON attendance_devices (device_sn)'
-          : 'CREATE UNIQUE INDEX IF NOT EXISTS idx_attendance_devices_device_sn ON attendance_devices (device_sn)',
+        'CREATE UNIQUE INDEX idx_attendance_devices_device_sn ON attendance_devices (device_sn)',
       );
     }
     await createIndex(
-      isMySQL
-        ? 'CREATE INDEX idx_attendance_devices_classroom_id ON attendance_devices (classroom_id)'
-        : 'CREATE INDEX IF NOT EXISTS idx_attendance_devices_classroom_id ON attendance_devices (classroom_id)',
+      'CREATE INDEX idx_attendance_devices_classroom_id ON attendance_devices (classroom_id)',
     );
   });
 }
@@ -94,8 +89,7 @@ export async function ensureStudentWalletSchema(
   dataSource: DataSource,
 ): Promise<void> {
   await withQueryRunner(dataSource, async (runner) => {
-    const isMySQL = dataSource.options.type === 'mysql';
-    const pk = isMySQL ? 'INTEGER PRIMARY KEY AUTO_INCREMENT' : 'INTEGER PRIMARY KEY AUTOINCREMENT';
+    const pk = 'INTEGER PRIMARY KEY AUTO_INCREMENT';
     await runner.query(`CREATE TABLE IF NOT EXISTS student_wallets (
         id ${pk}, student_id INTEGER NOT NULL UNIQUE, balance DECIMAL(12,2) NOT NULL DEFAULT 0,
         created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
@@ -140,9 +134,9 @@ export async function ensureStudentWalletSchema(
       const hasImportKey = refreshedRoomExpenses?.indices.some((index) =>
         index.isUnique && index.columnNames.length === 1 && index.columnNames[0] === 'import_key');
       if (!hasImportKey) {
-        await runner.query(isMySQL
-          ? 'CREATE UNIQUE INDEX idx_room_expenses_import_key ON room_expenses (import_key)'
-          : 'CREATE UNIQUE INDEX IF NOT EXISTS idx_room_expenses_import_key ON room_expenses (import_key)');
+        await runner.query(
+          'CREATE UNIQUE INDEX idx_room_expenses_import_key ON room_expenses (import_key)',
+        );
       }
     }
     const bills = await runner.getTable('bills');
diff --git a/apps/server/src/database/database-migrations.spec.ts b/apps/server/src/database/database-migrations.spec.ts
index 55a3b5d..c06b78c 100644
--- a/apps/server/src/database/database-migrations.spec.ts
+++ b/apps/server/src/database/database-migrations.spec.ts
@@ -40,7 +40,7 @@ function mockRunner(
   return { release, connect, query, getTables, getTable } satisfies MockRunner;
 }
 
-function createDataSource(runner: MockRunner, dbType: string = 'better-sqlite3') {
+function createDataSource(runner: MockRunner, dbType: string = 'mysql') {
   return {
     options: { type: dbType },
     createQueryRunner: jest.fn().mockReturnValue(runner),
@@ -81,7 +81,7 @@ describe('DatabaseMigrationsService — ensureAiConfigTable', () => {
     expect(runner.connect).toHaveBeenCalled();
     expect(runner.query).toHaveBeenCalledWith(expect.stringContaining('CREATE TABLE ai_config'));
     expect(runner.query).toHaveBeenCalledWith(
-      expect.stringContaining('CREATE UNIQUE INDEX IF NOT EXISTS uq_ai_config_singleton'),
+      expect.stringContaining('CREATE UNIQUE INDEX uq_ai_config_singleton ON ai_config(singleton_key)'),
     );
     expect(runner.release).toHaveBeenCalled();
   });
@@ -260,7 +260,7 @@ describe('DatabaseMigrationsService — course attendance schema', () => {
 describe('DatabaseMigrationsService — protectAttendanceHistory', () => {
   let service: MigrationsPrivate & DatabaseMigrationsService;
 
-  async function bootstrap(runner: MockRunner, dbType: string = 'better-sqlite3') {
+  async function bootstrap(runner: MockRunner, dbType: string = 'mysql') {
     const dataSource = createDataSource(runner, dbType);
     const module: TestingModule = await Test.createTestingModule({
       providers: [
@@ -279,107 +279,6 @@ describe('DatabaseMigrationsService — protectAttendanceHistory', () => {
     expect(runner.release).toHaveBeenCalled();
   });
 
-  it('SQLite: exits early when FKs already exist', async () => {
-    const runner = mockRunner({
-      getTables: [{ name: 'attendance_sessions', columns: [{ name: 'id' }] }],
-    });
-    runner.query.mockResolvedValueOnce([{ id: 0 }]); // PRAGMA foreign_key_list returns rows
-    await bootstrap(runner);
-    await service.protectAttendanceHistory();
-
-    // Should not run any TABLE creation (rebuild)
-    const queries: string[] = (runner.query as jest.Mock).mock.calls.map((c: unknown[]) =>
-      typeof c[0] === 'string' ? c[0] : '',
-    );
-    expect(queries.filter((q: string) => q.includes('CREATE TABLE'))).toHaveLength(0);
-    expect(runner.release).toHaveBeenCalled();
-  });
-
-  it('SQLite: rebuilds table with FK constraints when FKs are absent', async () => {
-    const runner = mockRunner({
-      getTables: [{ name: 'attendance_sessions', columns: [{ name: 'id' }] }],
-    });
-    // PRAGMA foreign_key_list for attendance_sessions → empty
-    runner.query.mockResolvedValueOnce([]);
-    // PRAGMA foreign_key_list for attendance_records → also empty (no FK yet)
-    runner.query.mockResolvedValueOnce([]);
-    await bootstrap(runner);
-    await service.protectAttendanceHistory();
-
-    const queries: string[] = (runner.query as jest.Mock).mock.calls.map((c: unknown[]) =>
-      typeof c[0] === 'string' ? c[0] : '',
-    );
-
-    // PRAGMA foreign_keys = OFF outside the transaction
-    expect(queries.some((q: string) => q.includes('PRAGMA foreign_keys = OFF'))).toBe(true);
-    expect(queries.some((q: string) => q.includes('CREATE TABLE attendance_sessions_new'))).toBe(
-      true,
-    );
-    expect(
-      queries.some((q: string) =>
-        q.includes('FOREIGN KEY (schedule_id) REFERENCES class_schedule(id) ON DELETE RESTRICT'),
-      ),
-    ).toBe(true);
-    expect(
-      queries.some((q: string) =>
-        q.includes('FOREIGN KEY (class_id) REFERENCES classes(id) ON DELETE RESTRICT'),
-      ),
-    ).toBe(true);
-    expect(queries.some((q: string) => q.includes('INSERT INTO attendance_sessions_new'))).toBe(
-      true,
-    );
-    expect(queries.some((q: string) => q.includes('DROP TABLE attendance_sessions'))).toBe(true);
-    expect(queries.some((q: string) => q.includes('RENAME TO attendance_sessions'))).toBe(true);
-    expect(queries.some((q: string) => q.includes('uq_attendance_session_schedule_date'))).toBe(
-      true,
-    );
-    // attendance_records rebuilt with FK
-    expect(queries.some((q: string) => q.includes('CREATE TABLE attendance_records_new'))).toBe(
-      true,
-    );
-    expect(queries.some((q: string) => q.includes('INSERT INTO attendance_records_new'))).toBe(
-      true,
-    );
-    expect(queries.some((q: string) => q.includes('DROP TABLE attendance_records'))).toBe(true);
-    expect(queries.some((q: string) => q.includes('uq_attendance_session_student'))).toBe(true);
-    // PRAGMA foreign_keys restored to ON and foreign_key_check runs
-    expect(queries.some((q: string) => q.includes('PRAGMA foreign_keys = ON'))).toBe(true);
-    expect(queries.some((q: string) => q.includes('PRAGMA foreign_key_check'))).toBe(true);
-    expect(runner.release).toHaveBeenCalled();
-  });
-
-  it('SQLite: rolls back transaction when foreign_key_check finds violations', async () => {
-    const runner = mockRunner({
-      getTables: [{ name: 'attendance_sessions', columns: [{ name: 'id' }] }],
-    });
-    // Use mockImplementation to match by SQL content, not call position
-    runner.query.mockImplementation((sql: string) => {
-      if (typeof sql === 'string' && sql.includes('PRAGMA foreign_key_list')) {
-        return Promise.resolve([]); // FKs absent → trigger rebuild
-      }
-      if (typeof sql === 'string' && sql.includes('PRAGMA foreign_key_check')) {
-        return Promise.resolve([
-          { table: 'attendance_sessions', rowid: 42, parent: 'class_schedule', fkid: 0 },
-        ]);
-      }
-      return Promise.resolve([]);
-    });
-    await bootstrap(runner);
-
-    await expect(service.protectAttendanceHistory()).rejects.toThrow(/外键一致性检查失败/);
-
-    const queries: string[] = (runner.query as jest.Mock).mock.calls.map((c: unknown[]) =>
-      typeof c[0] === 'string' ? c[0] : '',
-    );
-
-    // The transaction should have been rolled back (ROLLBACK called)
-    expect(queries.some((q: string) => q.includes('ROLLBACK'))).toBe(true);
-    // COMMIT should NOT have been called
-    expect(queries.some((q: string) => q.trim() === 'COMMIT')).toBe(false);
-    // PRAGMA foreign_keys should still be restored
-    expect(queries.some((q: string) => q.includes('PRAGMA foreign_keys = ON'))).toBe(true);
-    expect(runner.release).toHaveBeenCalled();
-  });
   it('MySQL: drops old FKs and recreates both schedule_id and class_id as RESTRICT', async () => {
     const runner = mockRunner({
       getTables: [{ name: 'attendance_sessions', columns: [{ name: 'id' }] }],
diff --git a/apps/server/src/migration-runner.ts b/apps/server/src/migration-runner.ts
index 4e9da94..f59f649 100644
--- a/apps/server/src/migration-runner.ts
+++ b/apps/server/src/migration-runner.ts
@@ -14,12 +14,7 @@ import { config } from 'dotenv';
 
 config();
 
-const isMySQL = (process.env.DB_TYPE || 'sqlite') === 'mysql';
-
 export async function runMigrationsOnStartup(): Promise<void> {
-  // 该迁移由 MySQL 生成；SQLite 开发环境由 AppModule 中的 TypeORM synchronize 建表。
-  if (!isMySQL) return;
-
   const ds = new DataSource({
     type: 'mysql',
     host: process.env.DB_HOST || 'localhost',
diff --git a/apps/server/src/migrations/1784900000000-EnlargeAiReviewSections.ts b/apps/server/src/migrations/1784900000000-EnlargeAiReviewSections.ts
index caeac05..561e962 100644
--- a/apps/server/src/migrations/1784900000000-EnlargeAiReviewSections.ts
+++ b/apps/server/src/migrations/1784900000000-EnlargeAiReviewSections.ts
@@ -12,10 +12,7 @@ export class EnlargeAiReviewSections1784900000000 implements MigrationInterface
     const column = table?.columns.find((item) => item.name === 'sections_json');
     const columnType = String(column?.type ?? '').toLowerCase();
     if (columnType === 'longtext') return;
-    if (queryRunner.connection.options.type === 'mysql') {
-      await queryRunner.query('ALTER TABLE ai_reviews MODIFY sections_json LONGTEXT');
-    }
-    // SQLite TEXT 无长度上限，无需变更。
+    await queryRunner.query('ALTER TABLE ai_reviews MODIFY sections_json LONGTEXT');
   }
 
   async down(_queryRunner: QueryRunner): Promise<void> {
diff --git a/apps/server/src/occupancies/occupancies.boundaries.spec.ts b/apps/server/src/occupancies/occupancies.boundaries.spec.ts
index 92fc1f2..5298a1c 100644
--- a/apps/server/src/occupancies/occupancies.boundaries.spec.ts
+++ b/apps/server/src/occupancies/occupancies.boundaries.spec.ts
@@ -30,7 +30,7 @@ function createQueryBuilderMock<T>(result: T | null): QueryBuilderMock<T> {
 
 function createTransactionDataSource(manager: Record<string, unknown>): DataSource {
   return {
-    options: { type: 'sqlite' },
+    options: { type: 'mysql' },
     transaction: jest.fn(
       async (fn: (manager: Record<string, unknown>) => unknown) => fn(manager),
     ),
@@ -105,7 +105,7 @@ function createQueryRunnerDataSource(config: {
   };
 
   return {
-    options: { type: 'sqlite' },
+    options: { type: 'mysql' },
     createQueryRunner: jest.fn().mockReturnValue({
       connect: jest.fn().mockResolvedValue(undefined),
       startTransaction: jest.fn().mockResolvedValue(undefined),
diff --git a/apps/server/src/occupancies/occupancies.service.spec.ts b/apps/server/src/occupancies/occupancies.service.spec.ts
index 372c435..d5254fd 100644
--- a/apps/server/src/occupancies/occupancies.service.spec.ts
+++ b/apps/server/src/occupancies/occupancies.service.spec.ts
@@ -31,7 +31,7 @@ function createQueryBuilderMock<T>(result: T | null): QueryBuilderMock<T> {
 
 function createTransactionDataSource(manager: Record<string, unknown>): DataSource {
   return {
-    options: { type: 'sqlite' },
+    options: { type: 'mysql' },
     transaction: jest.fn(async (fn: (manager: Record<string, unknown>) => unknown) => fn(manager)),
   } as any as DataSource;
 }
diff --git a/apps/server/src/occupancies/occupancies.service.ts b/apps/server/src/occupancies/occupancies.service.ts
index 6ba2d8e..96717a2 100644
--- a/apps/server/src/occupancies/occupancies.service.ts
+++ b/apps/server/src/occupancies/occupancies.service.ts
@@ -163,11 +163,7 @@ export class OccupanciesService {
   private withPessimisticWriteLock<T extends ObjectLiteral>(
     qb: SelectQueryBuilder<T>,
   ): SelectQueryBuilder<T> {
-    const type = this.dataSource.options.type;
-    if (type === 'mysql' || type === 'mariadb' || type === 'postgres' || type === 'cockroachdb') {
-      return qb.setLock('pessimistic_write');
-    }
-    return qb;
+    return qb.setLock('pessimistic_write');
   }
 
   private normalizePositiveMoney(value: number, label: string): number {
diff --git a/apps/server/src/occupancies/occupancy-lock.ts b/apps/server/src/occupancies/occupancy-lock.ts
index 3e7a16d..c47cd7f 100644
--- a/apps/server/src/occupancies/occupancy-lock.ts
+++ b/apps/server/src/occupancies/occupancy-lock.ts
@@ -2,11 +2,7 @@ import type { SelectQueryBuilder, ObjectLiteral, DataSource } from 'typeorm';
 
 export function withPessimisticWriteLock<T extends ObjectLiteral>(
   qb: SelectQueryBuilder<T>,
-  dataSource: DataSource,
+  _dataSource: DataSource,
 ): SelectQueryBuilder<T> {
-  const type = dataSource.options.type;
-  if (type === 'mysql' || type === 'mariadb' || type === 'postgres' || type === 'cockroachdb') {
-    return qb.setLock('pessimistic_write');
-  }
-  return qb;
+  return qb.setLock('pessimistic_write');
 }
diff --git a/apps/server/src/rooms/room-inspections.service.spec.ts b/apps/server/src/rooms/room-inspections.service.spec.ts
index b6d6c82..be420b2 100644
--- a/apps/server/src/rooms/room-inspections.service.spec.ts
+++ b/apps/server/src/rooms/room-inspections.service.spec.ts
@@ -70,7 +70,7 @@ describe('RoomInspectionsService', () => {
       }),
     } as unknown as EntityManager;
     const dataSource = {
-      options: { type: 'better-sqlite3' },
+      options: { type: 'mysql' },
       manager,
       transaction: jest.fn(async (callback) => callback(manager)),
     } as unknown as DataSource;
diff --git a/apps/server/src/rooms/room-inspections.service.ts b/apps/server/src/rooms/room-inspections.service.ts
index 7bf4d5f..6b8d476 100644
--- a/apps/server/src/rooms/room-inspections.service.ts
+++ b/apps/server/src/rooms/room-inspections.service.ts
@@ -206,9 +206,7 @@ export class RoomInspectionsService implements OnApplicationBootstrap {
     allowArchived: boolean,
   ): Promise<Room> {
     let query = manager.createQueryBuilder(Room, 'room').where('room.id = :roomId', { roomId });
-    if (['mysql', 'mariadb', 'postgres', 'cockroachdb'].includes(this.dataSource.options.type)) {
-      query = query.setLock('pessimistic_write');
-    }
+    query = query.setLock('pessimistic_write');
     const room = await query.getOne();
     if (!room) throw new BadRequestException('宿舍不存在');
     if (!allowArchived && room.status === 'archived') {
diff --git a/apps/server/src/wallets/wallets.service.spec.ts b/apps/server/src/wallets/wallets.service.spec.ts
index adf919f..740aac2 100644
--- a/apps/server/src/wallets/wallets.service.spec.ts
+++ b/apps/server/src/wallets/wallets.service.spec.ts
@@ -138,22 +138,6 @@ describe('WalletsService wallet locking', () => {
     };
   };
 
-  it('skips pessimistic locking for SQLite', async () => {
-    const ctx = createQueryManager();
-    const service = new WalletsService(
-      {} as any,
-      {} as any,
-      {} as any,
-      { options: { type: 'better-sqlite3' } } as any,
-    );
-
-    const result = await (service as any).getOrCreateWallet(ctx.manager, 10, true);
-
-    expect(result).toBe(ctx.wallet);
-    expect(ctx.query.setLock).not.toHaveBeenCalled();
-    expect(ctx.query.getOne).toHaveBeenCalled();
-  });
-
   it('keeps pessimistic write locking for MySQL', async () => {
     const ctx = createQueryManager();
     const service = new WalletsService(
diff --git a/apps/server/src/wallets/wallets.service.ts b/apps/server/src/wallets/wallets.service.ts
index 62a078e..009ae64 100644
--- a/apps/server/src/wallets/wallets.service.ts
+++ b/apps/server/src/wallets/wallets.service.ts
@@ -284,9 +284,7 @@ export class WalletsService {
       let query = manager
         .createQueryBuilder(StudentWallet, 'wallet')
         .where('wallet.studentId = :studentId', { studentId });
-      if (['mysql', 'mariadb', 'postgres', 'cockroachdb'].includes(this.dataSource.options.type)) {
-        query = query.setLock('pessimistic_write');
-      }
+      query = query.setLock('pessimistic_write');
       return query.getOne();
     };
     let wallet = await find();
diff --git a/package-lock.json b/package-lock.json
index d061824..9bc190e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -132,7 +132,6 @@
         "@nestjs/cli": "^11.0.0",
         "@nestjs/schematics": "^11.0.0",
         "@nestjs/testing": "^11.0.1",
-        "@types/better-sqlite3": "^7.6.13",
         "@types/express": "^5.0.0",
         "@types/jest": "^30.0.0",
         "@types/node": "^24.0.0",
@@ -148,9 +147,6 @@
         "tsconfig-paths": "^4.2.0",
         "typescript": "~6.0.2",
         "typescript-eslint": "^8.20.0"
-      },
-      "optionalDependencies": {
-        "better-sqlite3": "^12.9.0"
       }
     },
     "node_modules/@angular-devkit/core": {
@@ -5865,16 +5861,6 @@
         "@babel/types": "^7.28.2"
       }
     },
-    "node_modules/@types/better-sqlite3": {
-      "version": "7.6.13",
-      "resolved": "https://registry.npmmirror.com/@types/better-sqlite3/-/better-sqlite3-7.6.13.tgz",
-      "integrity": "sha512-NMv9ASNARoKksWtsq/SHakpYAYnhBrQgGD8zkLYk/jaK8jUGn08CfEdTRgYhMypUQAfzSP8W6gNLe0q19/t4VA==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "@types/node": "*"
-      }
-    },
     "node_modules/@types/body-parser": {
       "version": "1.19.6",
       "resolved": "https://registry.npmmirror.com/@types/body-parser/-/body-parser-1.19.6.tgz",
@@ -8290,6 +8276,7 @@
       "hasInstallScript": true,
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "bindings": "^1.5.0",
         "prebuild-install": "^7.1.1"
@@ -8326,6 +8313,7 @@
       "integrity": "sha512-p2q/t/mhvuOj/UeLlV6566GD/guowlr0hHxClI0W9m7MWYkL1F0hLo+0Aexs9HSPCtR1SXQ0TD3MMKrXZajbiQ==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "file-uri-to-path": "1.0.0"
       }
@@ -8745,7 +8733,8 @@
       "resolved": "https://registry.npmmirror.com/chownr/-/chownr-1.1.4.tgz",
       "integrity": "sha512-jJ0bqzaylmJtVnNgzTeSOs8DPavpbYgEr/b0YL8/2GO3xJEhInFmhKMUnEJQjZumK7KXGFhUy89PrsJWlakBVg==",
       "license": "ISC",
-      "optional": true
+      "optional": true,
+      "peer": true
     },
     "node_modules/chrome-trace-event": {
       "version": "1.0.4",
@@ -9923,6 +9912,7 @@
       "integrity": "sha512-aW35yZM6Bb/4oJlZncMH2LCoZtJXTRxES17vE3hoRiowU2kWHaJKFkSBDnDR+cm9J+9QhXmREyIfv0pji9ejCQ==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "mimic-response": "^3.1.0"
       },
@@ -9953,6 +9943,7 @@
       "integrity": "sha512-LOHxIOaPYdHlJRtCQfDIVZtfw/ufM8+rVj649RIHzcm/vGwQRXFt6OPqIFWsm2XEMrNIEtWR64sY1LEKD2vAOA==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "engines": {
         "node": ">=4.0.0"
       }
@@ -10853,6 +10844,7 @@
       "integrity": "sha512-XYfuKMvj4O35f/pOXLObndIRvyQ+/+6AhODh+OKWj9S9498pHHn/IMszH+gt0fBCRWMNfk1ZSp5x3AifmnI2vg==",
       "license": "(MIT OR WTFPL)",
       "optional": true,
+      "peer": true,
       "engines": {
         "node": ">=6"
       }
@@ -11049,7 +11041,8 @@
       "resolved": "https://registry.npmmirror.com/file-uri-to-path/-/file-uri-to-path-1.0.0.tgz",
       "integrity": "sha512-0Zt+s3L7Vf1biwWZ29aARiVYLx7iMGnEUl9x33fbB/j3jR81u/O2LbqK+Bm1CDSNDKVtJ/YjwY7TUd5SkeLQLw==",
       "license": "MIT",
-      "optional": true
+      "optional": true,
+      "peer": true
     },
     "node_modules/finalhandler": {
       "version": "2.1.1",
@@ -11531,7 +11524,8 @@
       "resolved": "https://registry.npmmirror.com/github-from-package/-/github-from-package-0.0.0.tgz",
       "integrity": "sha512-SyHy3T1v2NUXn29OsWdxmK6RwHD+vkj3v8en8AOBZ1wBQ/hCAQ5bAQTD02kW4W9tUp/3Qh6J8r9EvntiyCmOOw==",
       "license": "MIT",
-      "optional": true
+      "optional": true,
+      "peer": true
     },
     "node_modules/glob": {
       "version": "13.0.6",
@@ -12042,7 +12036,8 @@
       "resolved": "https://registry.npmmirror.com/ini/-/ini-1.3.8.tgz",
       "integrity": "sha512-JV/yugV2uzW5iMRSiZAyDtQd+nxtUnjeLt0acNdw98kKLrvuRVyB80tsREOE7yvGVgalhZ6RNXCmEHkUKBKxew==",
       "license": "ISC",
-      "optional": true
+      "optional": true,
+      "peer": true
     },
     "node_modules/inline-style-parser": {
       "version": "0.2.7",
@@ -14640,6 +14635,7 @@
       "integrity": "sha512-z0yWI+4FDrrweS8Zmt4Ej5HdJmky15+L2e6Wgn3+iK5fWzb6T3fhNFq2+MeTRb064c6Wr4N/wv0DzQTjNzHNGQ==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "engines": {
         "node": ">=10"
       },
@@ -14869,7 +14865,8 @@
       "resolved": "https://registry.npmmirror.com/mkdirp-classic/-/mkdirp-classic-0.5.3.tgz",
       "integrity": "sha512-gKLcREMhtuZRwRAfqP3RFW+TK4JqApVBtOIftVgjuABpAtpxhPGaDcfvbhNvD0B8iD1oUr/txX35NjcaY6Ns/A==",
       "license": "MIT",
-      "optional": true
+      "optional": true,
+      "peer": true
     },
     "node_modules/mrmime": {
       "version": "2.0.1",
@@ -15017,7 +15014,8 @@
       "resolved": "https://registry.npmmirror.com/napi-build-utils/-/napi-build-utils-1.0.2.tgz",
       "integrity": "sha512-ONmRUqK7zj7DWX0D9ADe03wbwOBZxNAfF20PlGfCWQcD3+/MakShIHrMqx9YwPTfxDdF1zLeL+RGZiR9kGMLdg==",
       "license": "MIT",
-      "optional": true
+      "optional": true,
+      "peer": true
     },
     "node_modules/napi-postinstall": {
       "version": "0.3.4",
@@ -15079,6 +15077,7 @@
       "integrity": "sha512-Cu6yUpX5Iavugm8BeX7c0wgU9CvOqfd1yM6A1d2q2ZMjym7GjpASv2GdRcTq3Fx+Sb5OgBkEEpw4VnAbY6Y5RA==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "semver": "^7.3.5"
       },
@@ -15092,6 +15091,7 @@
       "integrity": "sha512-Y7/KDsb8LjooZpwaqGyulO6DQlksgCncchHGk+sZIY4SBvUocMBEFH5Ur1fI4dV+Jvl0w6cjvucaIi40puRioA==",
       "license": "ISC",
       "optional": true,
+      "peer": true,
       "bin": {
         "semver": "bin/semver.js"
       },
@@ -15973,6 +15973,7 @@
       "integrity": "sha512-UnNke3IQb6sgarcZIDU3gbMeTp/9SSU1DAIkil7PrqG1vZlBtY5msYccSKSHDqa3hNg436IXK+SNImReuA1wEQ==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "detect-libc": "^2.0.0",
         "expand-template": "^2.0.3",
@@ -16102,6 +16103,7 @@
       "integrity": "sha512-VS7sjc6KR7e1ukRFhQSY5LM2uBWAUPiOPa/A3mkKmiMwSmRFUITt0xuj+/lesgnCv+dPIEYlkzrcyXgquIHMcA==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "end-of-stream": "^1.1.0",
         "once": "^1.3.1"
@@ -16190,6 +16192,7 @@
       "integrity": "sha512-y3bGgqKj3QBdxLbLkomlohkvsA8gdAiUQlSBJnBhfn+BPxg4bc62d8TcBW15wavDfgexCgccckhcZvywyQYPOw==",
       "license": "(BSD-2-Clause OR MIT OR Apache-2.0)",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "deep-extend": "^0.6.0",
         "ini": "~1.3.0",
@@ -16220,6 +16223,7 @@
       "integrity": "sha512-4gB8na07fecVVkOI6Rs4e7T6NOTki5EmL7TUduTs6bu3EdnSycntVJ4re8kgZA+wx9IueI2Y11bfbgwtzuE0KQ==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "engines": {
         "node": ">=0.10.0"
       }
@@ -17026,7 +17030,8 @@
         }
       ],
       "license": "MIT",
-      "optional": true
+      "optional": true,
+      "peer": true
     },
     "node_modules/simple-get": {
       "version": "4.0.1",
@@ -17048,6 +17053,7 @@
       ],
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "decompress-response": "^6.0.0",
         "once": "^1.3.1",
@@ -17555,6 +17561,7 @@
       "integrity": "sha512-OboTd8mmMhZDNPV+UjQcK9yKAatXu2aJ+r1w4im1Otd4M4fl2hwvdoXUxIYHFTHWK/3y3FarBP70v3vwmGlOxw==",
       "license": "MIT",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "chownr": "^1.1.1",
         "mkdirp-classic": "^0.5.2",
@@ -18216,6 +18223,7 @@
       "integrity": "sha512-McnNiV1l8RYeY8tBgEpuodCC1mLUdbSN+CYBL7kJsJNInOP8UjDDEwdk6Mw60vdLLrr5NHKZhMAOSrR2NZuQ+w==",
       "license": "Apache-2.0",
       "optional": true,
+      "peer": true,
       "dependencies": {
         "safe-buffer": "^5.0.1"
       },
diff --git a/package.json b/package.json
index 1ec0d36..be80561 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,7 @@
     "test": "turbo run test",
     "format": "turbo run format",
     "typecheck": "turbo run typecheck",
-    "clean": "rimraf apps/server/dist apps/admin/dist apps/server/dorm_billing.db node_modules apps/*/node_modules packages/*/node_modules"
+    "clean": "rimraf apps/server/dist apps/admin/dist node_modules apps/*/node_modules packages/*/node_modules"
   },
   "devDependencies": {
     "oxfmt": "^0.57.0",
diff --git a/技术文档.md b/技术文档.md
index f2ea5f0..8d61ff7 100644
--- a/技术文档.md
+++ b/技术文档.md
@@ -26,10 +26,10 @@
 ```
 前端 (React + Vite)          后端 (NestJS)           数据库
 ┌─────────────────┐     ┌──────────────────┐     ┌──────────┐
-│ React 19        │     │ NestJS 11        │     │ SQLite   │
-│ Ant Design 6    │────▶│ TypeORM 0.3      │────▶│ (开发)   │
-│ ECharts         │     │ JWT + Passport   │     │ MySQL 8  │
-│ Vite 8          │     │ ExcelJS + PDFKit │     │ (生产)   │
+│ React 19        │     │ NestJS 11        │     │ MySQL 8  │
+│ Ant Design 6    │────▶│ TypeORM 0.3      │────▶│          │
+│ ECharts         │     │ JWT + Passport   │     │          │
+│ Vite 8          │     │ ExcelJS + PDFKit │     │          │
 └─────────────────┘     └──────────────────┘     └──────────┘
 ```
 
@@ -51,7 +51,7 @@
 - class-validator（参数校验）
 - ExcelJS（Excel 导出）
 - PDFKit（PDF 导出）
-- SQLite / MySQL（双数据库支持）
+- MySQL 8（唯一支持的数据库）
 
 ---
 
@@ -199,7 +199,7 @@
 
 | 变量 | 说明 | 默认值 |
 |------|------|--------|
-| DB_TYPE | 数据库类型 | sqlite |
+| DB_TYPE | 数据库类型（仅支持 MySQL） | mysql |
 | DB_HOST | MySQL 主机 | localhost |
 | DB_PORT | MySQL 端口 | 3306 |
 | DB_USERNAME | 数据库用户 | root |