Обсуждение: Query FKey Constraint Table and Column Names

I need to find out which tables, and columns in that table, reference a
given table.

I would like to use the information_schema views, but am stuck at 7.3.X
right now.

Here is what I came up with so far
SELECT pcl.relname AS thistable,
    pcl1.relname AS referencesthistable
FROM ((pg_constraint pc JOIN pg_class pcl
    ON ((pc.conrelid = pcl.oid)))
    JOIN pg_class pcl1 ON ((pc.confrelid = pcl1.oid)));

which is fine as far as it goes.  What is not readily apparent is how to
get the column names.  I see there are conkey and confkey in
pg_constraint, which seem to be arrays of integers that might just
relate to attnum in pg_attribute.

Is there already a view/function that will get me this info, and if not,
am I barking up the right tree here?  I seldom tinker in system tables,
because I am too lazy to learn them, and because it seems to be bad
form.  They are none of my business, really.

Looking forward to the information_schema crutch!

Ian

Ian Harding <iharding@tpchd.org> writes:
> Is there already a view/function that will get me this info, and if not,
> am I barking up the right tree here?

I'd suggest using pg_get_constraintdef() to decipher the contents of the
pg_constraint row.

(In 7.3 I think this function only handles foreign-key constraints, but
that's what you wanted anyway...)

            regards, tom lane