-- ========================================
-- 为评查点系统添加外键约束
-- ========================================

-- 1️⃣ 为 evaluation_points 表添加外键约束
-- evaluation_point_groups_id 引用 evaluation_point_groups.id
ALTER TABLE evaluation_points
ADD CONSTRAINT fk_evaluation_points_group
FOREIGN KEY (evaluation_point_groups_id)
REFERENCES evaluation_point_groups(id)
ON DELETE SET NULL  -- 删除分组时，将评查点的分组ID设为NULL
ON UPDATE CASCADE;  -- 更新分组ID时，级联更新

-- 2️⃣ 为 evaluation_point_groups 表添加自引用外键约束
-- pid 引用同一个表的 id（父子关系）
ALTER TABLE evaluation_point_groups
ADD CONSTRAINT fk_evaluation_point_groups_parent
FOREIGN KEY (pid)
REFERENCES evaluation_point_groups(id)
ON DELETE CASCADE   -- 删除父分组时，级联删除子分组
ON UPDATE CASCADE;  -- 更新父分组ID时，级联更新

-- 添加注释
COMMENT ON CONSTRAINT fk_evaluation_points_group ON evaluation_points IS '评查点所属分组外键约束';
COMMENT ON CONSTRAINT fk_evaluation_point_groups_parent ON evaluation_point_groups IS '评查点分组父子关系自引用外键约束';

-- 验证外键约束是否创建成功
SELECT
    tc.table_name,
    tc.constraint_name,
    kcu.column_name,
    ccu.table_name AS foreign_table_name,
    ccu.column_name AS foreign_column_name
FROM information_schema.table_constraints AS tc
JOIN information_schema.key_column_usage AS kcu
    ON tc.constraint_name = kcu.constraint_name
    AND tc.table_schema = kcu.table_schema
JOIN information_schema.constraint_column_usage AS ccu
    ON ccu.constraint_name = tc.constraint_name
    AND ccu.table_schema = tc.table_schema
WHERE tc.constraint_type = 'FOREIGN KEY'
    AND tc.table_name IN ('evaluation_points', 'evaluation_point_groups')
ORDER BY tc.table_name, tc.constraint_name;