DELETE语句与REFERENCE冲突 [英] The DELETE statement conflicted with the REFERENCE

问题描述

我有一个带有客户ID的table_Project(链接到tbl_Customer).在tbl_Customer中，我有Customer_ID(作为密钥)和其他一些信息，例如电话，电子邮件等.

I have a table_Project with a CustomerID in it (linked to tbl_Customer). In tbl_Customer I have Customer_ID(as key) and some other info like Phone, Email etc.

要从Gridview中删除它，请使用以下DeleteCommand:

To delete it from the Gridview I use this DeleteCommand:

DeleteCommand="DELETE FROM [tbl_Customer] WHERE [Customer_ID] = @Customer_ID" 

但这给了我以下错误:

DELETE语句与REFERENCE约束"Klant_Relatie"冲突.数据库"Database_1"，表"dbo.tbl_Project"，"CustomerID"列中发生了冲突.该语句已终止.

但是通过更新CustomerInfo我没有得到任何错误.我已经看到了C#的不同解决方案，但是我使用.net

But with updating the CustomerInfo I do not get any error. I have seen different solutions for C# but I use .net

有什么主意吗?

推荐答案

您的问题与参照完整性有关.您不能删除某个表( table table_Project 中的某些记录当前正在引用的记录(从表 tbl_Customer 中)示例).除非您要更新密钥(在您的情况下为 CustomerID )，否则 UPDATE 与 DELETE 有所不同. UPDATE 修改记录，而 DELETE 删除记录.

Your problem has something to do with referential integrity. You cannot delete a record (from table tbl_Customer) which is currently being referenced by some records in a certain table (table table_Project for example). UPDATE is different from DELETE unless you are updating the key, in your case CustomerID. UPDATE modifies a record while DELETE removes the record.

看看这个例子，

tbl_Customer表

CustomerID  CustomerName
1           Hello
2           World

table_Project表

CustomerID  ProjectName
1           Webscripting
1           Database Maintenance

您总是可以在表 tbl_customer 的记录 2 上执行所需的任何操作，因为没有引用该记录的记录.但是在记录 1 中，除非删除表 table_Project 中的两条记录，否则无法将其删除.您可以修改列 CustomerName ，但如果仍被引用，则不能修改 CustomerID .

You can always do anything you want on record 2 of table tbl_customer because there is no record that is referencing to it. But in record 1, you can't delete it unless the two records from table table_Project are deleted. You can modify column CustomerName but not CustomerID is if still being referenced.

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