Question

我有3张桌子：

后
像
注释

表之间的关系是：

邮政表：postid PK
喜欢表：LikeID PK，postid FK，CommentID FK
评论表：CommentID PK，PostID FK，CommentReplybyID FK（自我加入纪念）

现在我必须从帖子表中删除帖子，但是我收到了错误。

我在下面使用此查询：

begin tran

declare @userid int = 68;
declare @postid int = 15;

delete from likes 
where postid = @postid and userid = @userid 

delete from comments 
where postid = @postid and userid = @userid

delete from post 
where postid = @postid and userid = @userid 

rollback tran

我收到这些错误：

Msg 547，Level 16，State 0，Line 8
  DELETE语句与SAME TABLE REFERENCE约束＆＃34; Comments_fk3＆＃34;冲突。冲突发生在数据库＆＃34; development-topthat＆＃34;，table＆＃34; dbo.Comments＆＃34;，column＆＃39; CommentReplyID＆＃39;。

Msg 547，Level 16，State 0，Line 9
  DELETE语句与REFERENCE约束冲突＆＃34; Likes_fk1＆＃34;。冲突发生在数据库＆＃34; development-topthat＆＃34;，table＆＃34; dbo.Likes＆＃34;，column＆＃39; PostID＆＃39;。

我在做错的地方需要帮助。怎么做到这一点？

Answer 1

通过CommentReplyID和自联接注释的外观，我怀疑你在评论表中有某种嵌套关系。

您需要删除CommentReplyId与您删除的评论相匹配的记录。

begin tran

declare @userid int = 68;
declare @postid int = 15;

-- are you sure userid should be used here?
delete from likes where postid = @postid and userid = @userid 

delete from comments c1 join comments c2 on c2.CommentReplyId = c1.CommentId where c1.postid = @postid and c1.userid = @userid

delete from comments where postid =@postid and userid = @userid

delete from post where postid = @postid and userid = @userid 

rollback tran

使用SQL Server中的外键从多个表中删除记录

1 个答案: