Check if a user-defined type already exists in PostgreSQL

Question

Say I have created some user-defined types in the DB,

i.e. CREATE TYPE abc ...

Is it then possible to determine if the user-defined type exists

Answer 1

The simplest solution I've found so far that copes with schemas, inspired by @Cromax's answer, is this:

DO $$ BEGIN
    CREATE TYPE my_type AS (/* fields go here */);
EXCEPTION
    WHEN duplicate_object THEN null;
END $$;

Just what you might expect really - we just wrap the CREATE TYPE statement in an exception handler so it doesn't abort the current transaction.