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Re: DB uniqueness constraints and dealing with them
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Re: DB uniqueness constraints and dealing with them


  • Subject: Re: DB uniqueness constraints and dealing with them
  • From: Jerome Chan <email@hidden>
  • Date: Fri, 04 Jul 2008 08:30:16 +0800

What about doing

save -> if error check to see if existing record exists and if so throw up a duplicate error ?


On Jul 4, 2008, at 7:52 AM, Q wrote:


On 04/07/2008, at 2:58 AM, Florijan Stamenkovic wrote:

Hi all,

While reading older discussions on dealing with DB uniqueness restraints I've found out that the EOGeneralAdaptorException thrown differs among databases. Is there some generic code that deals with this in absolute terms ( don't you just *love* the word absolute being used in conjunction with software :) ? If there is in WOnder, could someone please be so kind to point me in the right direction (which part of WOnder) so I can look at it?

Or should I write some pure EOF code like: Fetch -> Check uniqueness -> Create new record -> Save -> Fetch -> Check, or something along those lines?

I don't know about you but this just screams race condition to me. However unlikely it may be to happen trying to do uniqueness without using an atomic operation is extremely painful to get right, and difficult to test properly.


This would assume that I know which attributes should be unique in code, which can be done. I'd rather not deal with this like this, it seems a nuisance.

Thanks,
Flor
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-- Seeya...Q

Quinton Dolan - email@hidden
Gold Coast, QLD, Australia (GMT+10)
Ph: +61 419 729 806



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  • Follow-Ups:
    • Re: DB uniqueness constraints and dealing with them
      • From: Florijan Stamenkovic <email@hidden>
    • Re: DB uniqueness constraints and dealing with them
      • From: Lachlan Deck <email@hidden>
References: 
 >DB uniqueness constraints and dealing with them (From: Florijan Stamenkovic <email@hidden>)
 >Re: DB uniqueness constraints and dealing with them (From: Q <email@hidden>)

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