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Why are FK not deferrable by default [message #582420] Thu, 18 April 2013 04:59 Go to next message
Amine
Messages: 259
Registered: March 2010
Senior Member

Hi all,
Well, everything is in the title. In my point of view, deferrable FK (DFK) are stronger than non-deferrable FK (NDFK). In other words, every NDFK can be moved to DFK. Is there a performance issue ? Can any one explain me that by an example ?

Thanks in advance,

Amine
Re: Why are FK not deferrable by default [message #582424 is a reply to message #582420] Thu, 18 April 2013 05:15 Go to previous messageGo to next message
Michel Cadot
Messages: 58644
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
It is historical reason, deferrable constraints first did not exist, so default is not deferrable to be backward compatible.

Regards
Michel
Re: Why are FK not deferrable by default [message #582425 is a reply to message #582424] Thu, 18 April 2013 05:19 Go to previous message
Amine
Messages: 259
Registered: March 2010
Senior Member

Thank you !
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