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Re: protected ON DELETE CASCADE

From: "Oliver Elphick" <olly(at)lfix(dot)co(dot)uk>
To: Murray Hobbs <murray(at)efone(dot)com>
Cc: pgsql-novice(at)postgresql(dot)org
Subject: Re: protected ON DELETE CASCADE
Date: 2001-08-23 13:01:51
Message-ID: 200108231302.f7ND1poa017052@linda.lfix.co.uk (view raw or flat)
Thread:
Lists: pgsql-novice
Murray Hobbs wrote:
  >
  >here's my problem
  >
  >i have tables A, B, C, D
  >
  >A <- B
  >A <- C <- D
  >
  >i want to maintain integrity so that if A is deleted from then so is
  >anything referencing from B and C - no problem ON DELETE CASCADE
  >
  >but if there are any D's that point back to A (through composite key in
  >C) i don't want the delete to go ahead - at all - i want an error
  >message and condition
  
If the reference from D to C uses ON DELETE RESTRICT (or NO ACTION), that
should fail and thus cause the original DELETE to fail.

-- 
Oliver Elphick                                Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight                              http://www.lfix.co.uk/oliver
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