[GENERAL] pg_catalog tables don't have constraints? - Mailing list pgsql-general

From Neil Anderson
Subject [GENERAL] pg_catalog tables don't have constraints?
Date
Msg-id CAEKCySvWnoMKMxeyHkWtwcbg7Voopq4fswOh5DhfF-RAvznpHw@mail.gmail.com
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Responses Re: [GENERAL] pg_catalog tables don't have constraints?
List pgsql-general
Hi,

I've been exploring the pg_catalog tables and pointed a couple of
tools at it to extract an ER diagram for a blog post. At first I
thought it was a bug in the drawing tool but it appears that the
relationships between the pg_catalog tables are implicit rather than
enforced by the database, is that correct?

For example, pg_class has relnamespace which according to the
documentation refers to pg_namespace.oid
(https://www.postgresql.org/docs/current/static/catalog-pg-class.html),
yet there is no FK there as far as I can see. Maybe I am missing
something or there is an interesting story as to why?

Thanks,
Neil


--
Neil Anderson
neil@postgrescompare.com
https://www.postgrescompare.com



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