Hmmm. Definitly better then my code. 1. does not use the spurious tool_table 2. is surely safe on high traffic and against unintencialnal tool_table littering. yet, forces us to write down "SELECT" when we actually mean "UPDATE". This is sort of 'source code obfuscation' - it's not a very good practice, but only an aestetics issue. I can live with that. So, thenx for the hint. I'll surely use it. -R On Mon, 2006-11-20 at 16:59 +0100, Tomasz Ostrowski wrote: > On Mon, 20 Nov 2006, Rafal Pietrak wrote: > > > The most obvious construct I'd use is: > > UPDATE my_table set filed=newvalue WHERE > > my_function(input)=my_table.selector_field; > > but it's useless, since the function would have been be evaluated for > > every row of the table. > > -- Not tested > > create function update_my_table(newvalue, input) > returns void > volatile > language plpgsql > as $$ > declare > selector selector_field_type; > begin > selector := my_function(input); > update my_table set filed=newvalue > where my_table.selector_field=selector; > end; > $$; > > -- and then > > select update_my_table(newvalue, input); > > -- Not tested. > > Regards > Tometzky
