primary key and foreign key delete

Rawat

11y1.2k.NET

i make a form with primary key and foreign key when i delete data it show exception but i want it show in label how to do this?

5 Replies

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Pankaj Kumar Choudhary11y ago
Accepted answer
Hello @Rawat best method is that you should use exception handling in SQL SERver.
if you want to show message in label then first use a variable and use this variable to store the error
throw by system after that you can retrieve value from this variable and show into table

Demo:

Declare @val1 int;
Declare @val2 int;
DECLARE @msg [nvarchar](max);
BEGIN TRY
Set @val1=8;
Set @val2=@val1/0; /* you can put your deletion code here */
END TRY
BEGIN CATCH
SET @msg= Error_Message();
SELECT @msg; /* retrieve value from this variable */
END CATCH

If you have any doubt then please ask.........
Sujeet Suman11y ago
Pankaj has explained it really nicely.
Pankaj Kumar Choudhary11y ago
This is my pleasure that i helped you. If you have any problem related to Sql then please ask
me i will give my 100% and try to solve problems
Thanks..........
Rawat11y ago
this way is right. i also get a solution try and catch in catch part use labeland show message thanks for your response for the future i need your help .
Gohil Jayendrasinh11y ago

You can do this using CASCADE DELETE

If a record in the parent table is deleted, then the corresponding records in the child table will automatically be deleted. This is called a cascade delete in SQL Server.

Drop the existing foreign key constraint,

Add a new one with the ON DELETE CASCADE setting enabled.

ALTER TABLE dbo.T2   DROP CONSTRAINT FK_T1_T2   -- or whatever it's called

ALTER TABLE dbo.T2   ADD CONSTRAINT FK_T1_T2_Cascade

   FOREIGN KEY (EmployeeID) REFERENCES dbo.T1 (EmployeeID) ON DELETE CASCADE

Than

DELETE FROM dbo.T2 WHERE EmployeeID = 1052014