Display user-defined types and their details

Question

I've created a few new UDTs in PostgreSQL. However, now I have two problems:

1. how to see which UDTs have been defined?
2. how to see the columns defined within these UDTs?

Unfortunately, I couldn't find anything on that in the PostgreSQL documentation.

Answer 1

Does this get you started?

SELECT n.nspname AS schema,
        pg_catalog.format_type ( t.oid, NULL ) AS name,
        t.typname AS internal_name,
        CASE
            WHEN t.typrelid != 0
            THEN CAST ( 'tuple' AS pg_catalog.text )
            WHEN t.typlen < 0
            THEN CAST ( 'var' AS pg_catalog.text )
            ELSE CAST ( t.typlen AS pg_catalog.text )
        END AS size,
        pg_catalog.array_to_string (
            ARRAY( SELECT e.enumlabel
                    FROM pg_catalog.pg_enum e
                    WHERE e.enumtypid = t.oid
                    ORDER BY e.oid ), E'\n'
            ) AS elements,
        pg_catalog.obj_description ( t.oid, 'pg_type' ) AS description
    FROM pg_catalog.pg_type t
    LEFT JOIN pg_catalog.pg_namespace n
        ON n.oid = t.typnamespace
    WHERE ( t.typrelid = 0
            OR ( SELECT c.relkind = 'c'
                    FROM pg_catalog.pg_class c
                    WHERE c.oid = t.typrelid
                )
        )
        AND NOT EXISTS
            ( SELECT 1
                FROM pg_catalog.pg_type el
                WHERE el.oid = t.typelem
                    AND el.typarray = t.oid
            )
        AND n.nspname <> 'pg_catalog'
        AND n.nspname <> 'information_schema'
        AND pg_catalog.pg_type_is_visible ( t.oid )
    ORDER BY 1, 2;

In psql you can \set ECHO_HIDDEN on to make psql show you the queries used to generate the output of the \d... commands. I've found these queries to be very useful as a starting point when digging metadata out of databases.

Answer 2

You can also use the standard GUI pgAdmin:

Make sure types are enabled in the object browser (Options - Browser - Display)

To the left you see user-defined types in the chosen schema (question 1.).

The SQL pane to the right has the reverse engineered SQL script for the selected type (question 2.).
More details in the pane above that, like Dependents etc.