TSQL：获取受级联删除影响的所有表

Question

我正在寻找一个 SQL 脚本，该脚本将列出从表 X 中删除记录时将受到影响的所有表。它还应该列出“树”下受影响的依赖表，因为受影响的表将对其他表进行级联删除，这反过来又会影响其他人等等。

Answer 1

您可以使用递归 CTE 生成受影响表的完整层次结构，例如

WITH OnDelete AS
(   SELECT f.parent_object_id,
            f.referenced_object_id,
            RecursionLevel = 1,
            ObjectTree = CONVERT(VARCHAR(MAX), CONCAT(OBJECT_NAME(f.parent_object_id), ' --> ', OBJECT_NAME(f.referenced_object_id)))
    FROM sys.foreign_keys AS f
    WHERE f.delete_referential_action_desc = 'CASCADE'
    UNION ALL
    SELECT  od.parent_object_id,
            f.referenced_object_id,
            od.RecursionLevel + 1,
            ObjectTree = CONVERT(VARCHAR(MAX), CONCAT(od.ObjectTree, ' --> ', OBJECT_NAME(f.referenced_object_id)))
    FROM    OnDelete AS od
            INNER JOIN sys.foreign_keys AS f
                ON f.parent_object_id = od.referenced_object_id
                AND f.delete_referential_action_desc = 'CASCADE'

)
SELECT  BaseTable = OBJECT_NAME(od.parent_object_id),
        OnDelete = od.ObjectTree
FROM    OnDelete AS od
WHERE   NOT EXISTS
        (   SELECT  1
            FROM    OnDelete AS ex
            WHERE   ex.parent_object_id = od.parent_object_id
            AND     ex.ObjectTree LIKE CONCAT(od.ObjectTree, '%')
            AND     LEN(ex.ObjectTree) > LEN(od.ObjectTree)
        )
ORDER BY od.parent_object_id;

这将输出类似：

基表	删除时
T2	T2 --> T1
T3	T3 --> T2 --> T1
T4	T4 --> T3 --> T2 --> T1
T5	T5 --> T4 --> T3 --> T2 --> T1

db<>fiddle 示例