-- =============================================
-- Education 模块 — 练习会话与题目快照回滚
-- Ticket #6 / Migration 002
-- =============================================
--
-- WARNING: This file contains NO executable SQL.
-- Destructive rollback (DROP TABLE) requires manual operator verification.
--
-- Manual rollback procedure (operator must execute):
-- 1. Verify no other tables depend on these tables:
--      SELECT tc.table_name, kcu.column_name, ccu.table_name AS referenced_table
--        FROM information_schema.table_constraints tc
--        JOIN information_schema.key_column_usage kcu
--          ON tc.constraint_name = kcu.constraint_name
--        JOIN information_schema.constraint_column_usage ccu
--          ON tc.constraint_name = ccu.constraint_name
--       WHERE tc.constraint_type = 'FOREIGN KEY'
--         AND ccu.table_name IN ('education_practice_session', 'education_practice_question');
--    Result MUST be empty before proceeding.
--
-- 2. Verify the tables contain only data from this migration:
--      SELECT COUNT(*) AS session_count FROM education_practice_session;
--      SELECT COUNT(*) AS question_count FROM education_practice_question;
--    Operator must confirm these counts are acceptable to destroy.
--
-- 3. After verification, execute:
--      DROP TABLE IF EXISTS education_practice_question;
--      DROP TABLE IF EXISTS education_practice_session;
--
-- DO NOT uncomment or execute the lines below without operator verification.
-- -- DROP TABLE IF EXISTS education_practice_question;
-- -- DROP TABLE IF EXISTS education_practice_session;
