Thread

1. Re: UPDATE keyword

   Ian Harding <ianh@co.pierce.wa.us> — 2001-05-29T14:03:36Z

   True, true... but the next time I need the code to fire I would need ot remember that I had set it to 1 and set it to something else...
   
   Ian A. Harding
   Programmer/Analyst II
   Tacoma-Pierce County Health Department
   (253) 798-3549
   mailto: ianh@tpchd.org
   
   >>> Rene Pijlman <rpijlman@spamcop.net> 05/26/01 01:56AM >>>
   ianh@healthdept.co.pierce.wa.us ("Ian Harding") schreef:
   >UPDATE mytable SET myfield = myfield WHERE...
   >to fire an update trigger, and executing only the code in that 
   >trigger surrounded by UPDATE(myfield).
   
   So you update a field by not changing its value, to execute a piece of
   code that has nothing to do with the field and the value :-)
   
   >Is there an easy way to duplicate this, or should I work around it?
   
   Isn't it easier (and more poratble) to add a dummy field to the table?
   Then you can do:
   
      UPDATE mytable
      SET dummy = 1 - dummy
      WHERE ...
   
   to execute the piece of code that responds to an update of 'dummy'.
   
   Regards,
   René Pijlman
   
   http://www.applinet.nl 
   
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2. Re: UPDATE keyword

   Rene Pijlman <rpijlman@spamcop.net> — 2001-05-29T16:38:29Z

   ianh@co.pierce.wa.us ("Ian Harding") schreef:
   >True, true... but the next time I need the code to fire I would 
   >need ot remember that I had set it to 1 and set it to something else...
   
   False, false, I've thought of that :-)
   
   The statement says:
   
   	dummy = 1 - dummy
   
   a) Initially, dummy == 0. Then dummy becomes 1 - 0 which equals 1.
   
   b) So dummy == 1. Then dummy becomes 1 - 1 which equals 0.
   
   c) Goto a.
   
   Dummy changes value from 0->1 or 1->0 on every execution of the
   statement.
   
   If you don't believe it, you can also try dummy = -dummy, but then you
   have to remember to initialize it to a non-zero value :-)
   
   -- 
   Vriendelijke groet,
   René Pijlman <rpijlman@spamcop.net>
   
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