On 02/04/10 17:17 +0200, Mathias Behrle wrote:
> > Any way, when looking at the comments in oracle thread, I thought about a
> > solution.
> > We could add a third integer field with the same value then "parent" but
> > without the foreign constraint. It will be filled by COALESCE("parent", -1).
> > The unique constraint will become:
> >
> > UNIQUE("name", "parent_")
> >
> > We could add a constraint to ensure that both values are always sync:
> >
> > CHECK(COASLESCE("parent", -1) = "parent_")
> >
> > The "parent_" field will be filled by the override of create and write
> > functions.
> >
> > I know this sounds a little bit hacking but this is my best solution :-)
>
> So if this is a solution, that can be used in general for all DBMS in Tryton,
> I
> think the overhead and hackish appearence caused by it is compensated by its
> overall benefit.
> Yes it will work for any DBMS that handle UNIQUE constraint (PostgreSQL, MySQL and SQLite). -- Cédric Krier B2CK SPRL Rue de Rotterdam, 4 4000 Liège Belgium Tel: +32 472 54 46 59 Email/Jabber: [email protected] Website: http://www.b2ck.com/
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