INFO: Trigger Execute Even if No Rows Affected by SQL Statement (124015)


The information in this article applies to:

  • Microsoft SQL Server 4.2x
  • Microsoft SQL Server 6.0
  • Microsoft SQL Server 6.5
  • Microsoft SQL Server 7.0
  • Microsoft SQL Server 2000 (all editions)
This article was previously published under Q124015

SUMMARY

An insert, update, or delete trigger will be executed even if the SQL statement referencing the trigger table did not affect any rows.

MORE INFORMATION

If the conditions of an INSERT, UPDATE, or DELETE statement result in an empty result set, a trigger associated with the table in the statement will still be executed.

If this behavior needs to be accounted for in the trigger source code, the trigger developer can examine the @@ROWCOUNT global variable as the first statement in the trigger. Remember that any Transact-SQL statement that does not return rows (such as an IF statement) sets @@ROWCOUNT to 0. An alternative to this approach is to examine the count of rows in the inserted and/or deleted table depending whether the trigger is for insert, update, or delete purposes.

For additional information on the behavior of the IF UPDATE statement under these conditions, please see the following article in the Microsoft Knowledge Base:

64238 : PRB: IF UPDATE Trigger with No Rows Changed


Modification Type:MinorLast Reviewed:2/22/2005
Keywords:kbinfo kbProgramming kbusage KB124015
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