SQL Update query invokes two rows in a trigger

Question

I am using SQL Server 2005 and ask the following question:

On table AI have a trigger that tracks any insert / update / delete. Tracked records are inserted into the audit table ( aAudit). When I run the update on A, I see two rows in the audit table for each update, which I do not expect. Here is the trigger that I defined:

ALTER TRIGGER [ATrigger] ON [dbo].[A]
FOR INSERT, UPDATE, DELETE
AS
INSERT INTO [dbo].[aAudit]
([BusinessDate], [DataTypeId], [BookId], [Version], [DelFlag], [AuditDate], [ExtStatus])
SELECT [BusinessDate], [DataTypeId], [BookId], [Version], 'N', getDate(), 0
FROM inserted

INSERT INTO [dbo].[aAudit]
([BusinessDate], [DataTypeId], [BookId], [Version], [DelFlag], [AuditDate], [ExtStatus])
SELECT [BusinessDate], [DataTypeId], [BookId], [Version], 'Y', getDate(), 0
FROM deleted

Why does the above trigger result in one row c DelFlag = 'Y'and one row c DelFalg = 'N'in the audit table?

Thanks for watching my question.

Vikram

Answer 1

INSERT, UPDATE, DELETE, :

ALTER TRIGGER [ATrigger] ON [dbo].[A]
FOR INSERT, UPDATE, DELETE
AS
   -- those are true INSERTs - the (ID) as primary key is *not* present in the "Deleted" table
   INSERT INTO [dbo].[aAudit]([BusinessDate], [DataTypeId], [BookId], [Version], [DelFlag], [AuditDate], [ExtStatus])
      SELECT [BusinessDate], [DataTypeId], [BookId], [Version], 'N', getDate(), 0
      FROM inserted 
      WHERE (id) NOT IN (SELECT DISTINCT (id) FROM DELETED)

   -- those are true DELETEs - the (ID) as primary key is *not* present in the "Inserted" table
   INSERT INTO [dbo].[aAudit]([BusinessDate], [DataTypeId], [BookId], [Version], [DelFlag], [AuditDate], [ExtStatus])
      SELECT [BusinessDate], [DataTypeId], [BookId], [Version], 'Y', getDate(), 0
      FROM deleted
      WHERE (id) NOT IN (SELECT DISTINCT (id) FROM INSERTED)

   -- those are the UPDATEs - the (ID) as primary key is present in both the "Inserted" and "Deleted" table
   INSERT INTO [dbo].[aAudit]([BusinessDate], [DataTypeId], [BookId], [Version], [DelFlag], [AuditDate], [ExtStatus])
      SELECT [BusinessDate], [DataTypeId], [BookId], [Version], 'N', getDate(), 0
      FROM Inserted i
      INNER JOIN Deleted d on i.ID = d.ID

Answer 2

UPDATE DELETE INSERT - . , , INSERTED DELETED .

UPDATE.