Get primary keys dynamically, via a C extention

[naddika]

This isn't directly related to this project; perhaps you know the answer:

I'm writting an extention in C. It's a function for a trigger. I need to dynamically identify which column, or columns, if the primary key is composed of multiple columns, is the primary key -- their indexes or names.

I suppose, the function get_primary_key_attnos can help me.

postgresql_projects/src/include/catalog/pg_constraint.h

Line 236 in 5afaa2e

extern Bitmapset *get_primary_key_attnos(Oid relid, bool deferrableOk,

It returns *Bitstamp. And it's got "nwords" and "words[]". But those return just big numbers, not something that look similar to an index of the primary key column.

Therefore, I haven't been able to figure out how to proceed with it and identify the primary key. Any idea?

[RhodiumToad]

You should ask this on the pgsql-general mailing list or on the #postgresql irc channel on freenode.

But a Bitmapset is a set of small integers represented as a bitmap, and there are functions to iterate over it and return the contained integer values; these are the attnos of the primary key columns.