On Wed, Apr 11, 2007 at 09:21:46AM -0700, Chris Travers wrote: > DO ALSO rules involving NEW are fundamentally dangerous to the integrity > of data because NEW is not guaranteed to be internally consistent. DO > INSTEAD rules are fine (there is only one NEW), as are any DO ALSO rules > involving OLD. Huh? The entered data is exactly what was asked. The whole system is totally deterministic and works as designed. Really, I'd prefer a warning stating that people shouldn't use rules unless they absolutly know what they're doing. > One of the things that causes me to favor PostgreSQL for all my projects > is the strong emphasis on data integrity by the community, perhaps > better than any other RDBMS out there. Being unwilling to warn clearly > and loudly about unsafe features does undermine that commitment. The problem is that the are some things that really need rules. However, I think you can safely say: Unless what you want can only be done using rules, use triggers. They are far more obivous. Not to mention that using a rule for auditing is silly, since it won't record what actually went into the table. > For 90% of what I do, I use the local copy of the docs. My concern is > that (at least in 8.1) there is no obvious warning about DO ALSO rules > using NEW to be inherently nondeterministic. Wrong word. It's not non-deterministic, nor is it undocumented, it's just often misunderstood. Which brings you back to: if it doesn't have to be a rule, make it a trigger. Forget you ever heard about rules. Pretend they don't exist... Have a nice day, -- Martijn van Oosterhout <kleptog@xxxxxxxxx> http://svana.org/kleptog/ > From each according to his ability. To each according to his ability to litigate.
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