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Column Triggers

  • January 17, 2006 at 3:36 pm

    #90446

    I am currently trying to implement update triggers on a table containing a total of 44 columns. I want to specify that the triggers should fire only when any of columns 1-15 are updated. Now I've tried to implement the columns_updated() statement within the trigger, but I must be screwing up the bitmask somewhere. The coniditional statement I used was:

    IF (COLUMNS_UPDATED() & 32767) > 0

    Am I making a miscalculation somewhere? Even when I update a column greater than 15 (like the end column), the trigger still fires...

    HELP!

    Thanks in advance

    -A

  • January 17, 2006 at 3:58 pm

    #615325

    Hi,

    I did not try it myself, but did you follow the example in

    http://msdn2.microsoft.com/en-us/library/ms186329.aspx

    It says in the middle after the first example:

    To test for updates that affect columns other than the first eight columns in a table, use the SUBSTRING function to test the correct bit returned by COLUMNS_UPDATED

    Then the example follows for the fields 3,5 9

    .............

    IF ( (SUBSTRING(COLUMNS_UPDATED(),1,1)=power(2,(3-1))

          + power(2,(5-1)))

          AND (SUBSTRING(COLUMNS_UPDATED(),2,1)=power(2,(1-1)))

          )

       PRINT 'Columns 3, 5 and 9 updated';

    It may be related that it is only 8 bits in a byte

    Regards,Yelena Varsha

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