Re: Tables Referencing themselves As Foreign Keys
От | Arjen van der Meijden |
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Тема | Re: Tables Referencing themselves As Foreign Keys |
Дата | |
Msg-id | 3FE6D74F.2070903@vulcanus.its.tudelft.nl обсуждение исходный текст |
Ответ на | Tables Referencing themselves As Foreign Keys ("Tony (Unihost)" <tony@unihost.net>) |
Ответы |
Re: Tables Referencing themselves As Foreign Keys
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Список | pgsql-general |
Tony, That'll work, but you have to mind the first row/toprow you insert. Will it have no parent (make the field nullable) or will it be its own parent (you'll have to test whether that works, I don't know, foreign keys are deferrable, so it should be possible if you specify that). Best regards, Arjen Tony (Unihost) wrote: > Hi, > > I'm still new to this so if I'm sounding dumb or my premise is flawed > please forgive me. I have a DB design which contains a table which has > categories, each category has a parent category, and is recursed until > the top category is reached, in order to create breadcrumbs. Is there > any problem with using foreign keys to reference the same table? So a > when category is added the CatParent MUST be present as a CatID > > CatID - Serial > CatParent - int4 - References CatID > CatName - Text > > Am I likeley to come unstuck with this? > > Cheers > > T.
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