Re: Getting FK relationships from information_schema

Tom Lane wrote:

>Kyle <kyle(at)actarg(dot)com> writes:
>
>
>>The problem is, the constraint names ($1,
>>$2, etc.) are not unique so I don't know how to join the third query
>>into the fourth.
>>
>>
>
>Hmm, this is messy :-(. The SQL spec requires constraint names to be
>unique within a schema. Postgres doesn't require them to be unique even
>within a table.
>
I think this is only an issue when the user relies on postgres to choose
a constraint name automatically. Seems like a reasonable approach would
be to have postgres choose a name for the constraint that happens to be
unique in the schema (like tablename_fkey_$1). Then if the user wants
to make named constraints that all have the same name, he can (and
information_schema will be less useful) or he can rely on the
automatically generated names to be a bit more descriptive in
information_schema.

>Can we get away with adding
>implementation-specific columns to information_schema tables?
>If not, what other alternatives are there?
>
>
>
Another possible approach: Does the constraint name showing up in
information_schema really have to be the _real_ name? Or can we just
make a name consisting of the table name appended to the internal
postgres constraint name.

I think I like this less than the first idea.

Kyle