Question

I have a trigger in students table that deletes related records from other tables when i delete a student. I want to delete student’s membership data by calling aspnet_delete_user stored procedure in the trigger . but this works just if I delete one student . and if I remover multiple students in one query it doesn’t work .

How to call this SP for multi-row operation trigger ?

Answer 1

You’d have to use a cursor or build a dynamic SQL string (which uses a cursor without saying so). Alternatively, you could copy the logic from the stored procedure and see if you can tailor it to become set-based – I haven’t looked at the procedure, so I’m not sure if this is feasible, practical or even possible, but it’s the first thing I try to do before adding cursors or dynamic SQL to a trigger.

For a cursor, something like this (I’m guessing you pass a GUID or something to the procedure, but I have no idea):

CREATE TRIGGER dbo.StudentAfterDelete
ON dbo.Students
AFTER DELETE
AS
BEGIN
  SET NOCOUNT ON;

  DECLARE @MemberID UNIQUEIDENTIFIER;

  DECLARE c CURSOR LOCAL STATIC FORWARD_ONLY READ_ONLY
    FOR SELECT MemberID FROM deleted;

  OPEN c;

  FETCH NEXT FROM c INTO @MemberID;

  WHILE @@FETCH_STATUS <> -1
  BEGIN
    EXEC dbo.aspnet_delete_user @MemberID;

    FETCH NEXT FROM c INTO @MemberID;
  END

  CLOSE c;
  DEALLOCATE c;
END
GO

Dynamic SQL, same assumptions:

CREATE TRIGGER dbo.StudentAfterDelete
ON dbo.Students
AFTER DELETE
AS
BEGIN
  SET NOCOUNT ON;

  DECLARE @sql NVARCHAR(MAX) = N'';

  SELECT @sql += 'EXEC dbo.aspnet_delete_user ''' 
    + CONVERT(VARCHAR(36), MemberID) + ''';' FROM deleted;

  EXEC sp_executesql @sql;
END
GO

However including the missing information up front is more useful. Don’t assume that everyone who works with SQL Server has any clue what aspnet_delete_user does.