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Thread: Cross database foreign keys

Cross database foreign keys

From
Morgan Curley
Date:
Does anyone know if it is possible to connect to a differernt db from within a plsql function.
I have multilple inter-related schemas and want to enforce some fk relationships.

Thanks,
Morgan 

Re: [GENERAL] Cross database foreign keys

From
Jan Wieck
Date:
Morgan Curley wrote:
> Does anyone know if it is possible to connect to a differernt db from
> within a plsql function.
> I have multilple inter-related schemas and want to enforce some fk
> relationships.

    PL/pgSQL  doesn't support external database connects. PL/TclU
    does.

    But keep in mind that with this kind of setup you don't  have
    two  phase  commits,  and  that  updates  done through such a
    trigger (e.g. cascades)  will  not  rollback  if  your  local
    update does so after it got fired, because you have to commit
    the remote transaction before you know if your local one ever
    will.


Jan

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Re: Cross database foreign keys

From
"Josh Berkus"
Date:
Morgan,

> Does anyone know if it is possible to connect to a differernt db from
> within a plsql function.
> I have multilple inter-related schemas and want to enforce some fk
> relationships.

Currently Postgres does not support any SQL operations between
databases.  It may someday in the future, but then again it may not
(it's a design philosophy issue, I believe).

I don't know of *any* RDBMS that allows foriegn keys between databases!
If referential integrity is your goal, why on earth is the related data
in two different databases?

-Josh Berkus

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Re: Cross database foreign keys

From
Peter Eisentraut
Date:
Morgan Curley writes:

> Does anyone know if it is possible to connect to a differernt db from
> within a plsql function.
> I have multilple inter-related schemas and want to enforce some fk
> relationships.

Not possible

--
Peter Eisentraut   peter_e@gmx.net   http://funkturm.homeip.net/~peter