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swtirs

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How to identify what action caused the trigger to fire

I have a common trigger that is executed after insert, update and delete. I need to know what action caused the trigger to fire. for example the trigger fired becaused of a row deleted or bcos a row added etc.
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Dishan Fernando
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put this into trigger

INSERT INTO Table1(INSERT)
SELECT COUNT(*)
FROM Inserted

u can alse do this for "deleted" and "updated" trigger tables
I do not think there is an "updated" table in a trigger.

But if you have a primary key you might be able to use something like the idea.  Choose a column, say pkcol, that is part of the PK, and say it's an int. (I have not tested this)

declare @pkinserted  int
declare @pkdeleted   int
set @pkinserted = pkcol from inserted
set @pkdeleted = pkcol from deleted

if  @pkinserted is null and @pkdeleted is not null
  begin
   -- trigger is from delete
  end

if  @pkinserted is not null and @pkdeleted is not null
  begin
   -- trigger is from update
  end

if  @pkinserted is not null and @pkdeleted is null
  begin
   -- trigger is from insert
  end
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nmcdermaid

If it was an insert there will be rows in INSERTED and no rows in DELETED

If it was an update there will be rows in INSERTED and rows in DELETED

If it was a deletion there will be rows in DELETED and no rows in INSERTED.

These are all 'virtual tables' accessible from your trigger.
If you full outer join the inserted and deleted tables on the primary key you can tell.


EG:

SELECT CASE WHEN d.ID IS NULL THEN 'inserted' WHEN i.ID IS NULL THEN 'deleted' ELSE 'updated' END TypeOfOperation
FROM INSERTED i
   FULL OUTER JOIN DELETED d ON i.ID=d.ID
ASKER CERTIFIED SOLUTION
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namasi_navaretnam
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Perhaps, I am being stupid but.  Having mulled over this question all afternoon,  I am still biemused as to this question..........

Why do you need to know what operation caused the trigger to fire?

Why dont you simply have an INSERT trigger and UPDATE trigger and a DELETE trigger?