实现删除主表数据时, 判断与之关联的外键表是否有数据引用, 有标志, 无则删除

问题描述：某个基础信息表，与系统中30多个表存在外键关系，当删除基础数据时，需要判断是否已经被用过，如果用过则更改标志位，如果没有用过则直接删除，如何能很好实现这个处理？最好能够自动适应表的变化 问题解决（SQL Server 2005）-- SQL Server 2005的错误处理容易控制, 因此， SQL Server 2005中可以直接删除, 通过错误处理来确定是否需要更新. -- 示例如下.USE tempdbGO CREATE TABLE m(    id int PRIMARY KEY,     bz bit)INSERT m SELECT 1, 0UNION ALL SELECT 2, 0 CREATE TABLE c(    id int primary key,     a_id int references m(id)         ON DELETE NO ACTION)INSERT c SELECT 1, 1GO -- 删除处理存储过程CREATE PROC dbo.p_delete    @id intASSET NOCOUNT ONBEGIN TRYBEGIN TRAN    DELETE FROM m WHERE id = @idCOMMIT TRANEND TRYBEGIN CATCH     ROLLBACK TRAN    IF ERROR_NUMBER() = 547 -- 如果是外键约束错误    BEGIN        BEGIN TRY        BEGIN TRAN          -- 更新标志            UPDATE m SET bz = 1            WHERE id = @id        COMMIT TRAN        END TRY        BEGIN CATCH            SELECT ERROR_NUMBER(), ERROR_MESSAGE()        END CATCH    END    ELSE        SELECT ERROR_NUMBER(), ERROR_MESSAGE()END CATCHGO -- 调用EXEC dbo.p_delete 1EXEC dbo.p_delete 2SELECT * FROM mSELECT * FROM cGO DROP TABLE c, mDROP PROC dbo.p_delete 问题解决（SQL Server 2000）-- SQL Server 2000 对错误处理不好控制, 一般还是建议做判断-- 通过系统表查询系统表，可以获取某个表关联的所有外键表 -- 示例存储过程CREATE PROC dbo.p_Delete    @tbname sysname,        -- 基础数据表名    @PkFieldName sysname,   -- 基础数据表关键字段名    @PkValue int            -- 要删除的基础数据表关键字值ASSET NOCOUNT ONDECLARE @bz bit, @s nvarchar(4000)DECLARE tb CURSOR LOCALFORSELECT N'SET @bz = CASE WHEN EXISTS(        SELECT * FROM ' + QUOTENAME(@tbname)         + N' A, ' + QUOTENAME(OBJECT_NAME(B.fkeyid))        + N' B        WHERE A.' + QUOTENAME((SELECT name FROM syscolumns WHERE colid = B.rkey AND id = B.rkeyid))        + N' = B.' + QUOTENAME((SELECT name FROM syscolumns WHERE colid = B.fkey AND id = B.fkeyid))        + N' AND A.' + QUOTENAME((SELECT name FROM syscolumns WHERE colid = B.rkey AND id = B.rkeyid))        + N' = @id) THEN 1 ELSE 0 END'FROM sysobjects A    JOIN sysforeignkeys B        ON A.id=  B.constid    JOIN sysobjects C         ON A.parent_obj = C.idWHERE A.xtype = 'f'     AND C.xtype = 'U'    AND OBJECT_NAME(B.rkeyid) = @tbnameOPEN tbFETCH tb INTO @sWHILE @@FETCH_STATUS = 0BEGIN    EXEC sp_executesql @s, N'@tbname sysname, @id int, @bz bit OUT', @tbname, @PkValue, @bz OUT    IF @bz = 1    BEGIN        SET @s = N'UPDATE ' + QUOTENAME(@tbname)             + N' SET bz = 1 WHERE ' + QUOTENAME(@PkFieldName)            + N' = @id'        EXEC sp_executesql @s, N'@id int', @PkValue         RETURN    END     FETCH tb INTO @sENDCLOSE tbDEALLOCATE tb SET @s = N'DELETE FROM ' + QUOTENAME(@tbname)     + N' WHERE ' + QUOTENAME(@PkFieldName)    + N' = @id'EXEC sp_executesql @s, N'@id int', @PkValueGO 注意事项设置表的主/外键关系的时候，不要设置级联删除（ON DELETE CASCADE）  

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