| From: | Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> |
|---|---|
| To: | "David M(dot) Richter" <d(dot)Richter(at)dkfz-heidelberg(dot)de> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Referential Integrity --> SystemTables |
| Date: | 2001-09-03 17:28:01 |
| Message-ID: | Pine.BSF.4.21.0109031024430.76325-100000@megazone23.bigpanda.com |
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| Thread: | |
| Lists: | pgsql-general |
On Mon, 3 Sep 2001, David M. Richter wrote:
> Hello!
>
> I want to update a old postgresdatabase. In the time of databasecreation
> the postgres had no "references" construct. So the integrity is
> maintained by the C-Driver.
> Now I want to build in the integrity. But i have to maintain
> compatibiliy to old databases in the code itself.
> So my question:
> HOW can I determine if the database has referential integrity used or
> not? Are there in the database any "references" in use or not?
> Maybe it is descripted in any systemtable(pg_xyz)?
Do you mean determining if it supports it or if this database has
constraints defined? In the former case you pretty much need to do it by
version number probably (7.0+ have it). In the latter case, you need to
parse out the information from pg_trigger (there are three triggers per fk
constraint, most of the interesting information is in the tgargs column)
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