有没有办法显示用户定义的 postgresql 枚举类型定义？

Question

Let's say we've defined a postgresql type:

CREATE TYPE my_type AS ENUM('foo', 'bar');

Is there any way to show the type definition after creation ?

I would expect "\\d my_type" to show me "ENUM('foo', 'bar')", but it says :

Did not find any relation named "my_type"

The pg_type table doesn't seem to give enough information.

Answer 1

Check this:

select enum_range(null::my_type)

I think this is a much simpler solution :).

Answer 2

It's \\dT you're after, but it doesn't give it as a "CREATE" statement. You use \\dD for domains.

\dT+ action.action_status
                          List of data types
 Schema |         Name         | Internal name | Size | Elements | Description 
--------+----------------------+---------------+------+----------+-------------
 action | action.action_status | action_status | 4    | pending +| 
        |                      |               |      | live    +| 
        |                      |               |      | done    +| 
        |                      |               |      | notdone  | 
(1 row)

Answer 3

If you just want the full name (type name and schema) and a sorted list of all enum labels, this query will do:

SELECT n.nspname AS "schema", t.typname
     , string_agg(e.enumlabel, '|' ORDER BY e.enumsortorder) AS enum_labels
FROM   pg_catalog.pg_type t 
JOIN   pg_catalog.pg_namespace n ON n.oid = t.typnamespace 
JOIN   pg_catalog.pg_enum e ON t.oid = e.enumtypid  
WHERE  t.typname = 'my_enum_type'
GROUP  BY 1,2;

Returns:

 schema | typname      | enum_labels
--------+--------------+-------------
 public | my_enum_type | foo|bar

string_agg() requires Postgres 9.0 or later, replace with array_agg() for older versions.

---

To get the SQL CREATE statement, you could use pg_dump and look at the dump file.

Or, much more practically, use pgAdmin which displays reverse engineered SQL create scripts for any object in the database. Select it in the object browser and its create script is displayed in the SQL pane . There is even an option to copy the script to a newly opened window of the SQL editor automatically, where you can edit and execute it.

Answer 4

SELECT t.typname
FROM pg_class c JOIN pg_attribute a ON c.oid = a.attrelid JOIN pg_type t ON a.atttypid = t.oid
WHERE c.relname = 'your_type';

The tricky part was that simply selecting * from these views one does not get OIDs in the results.

Answer 5

using this post , I've archived the goal to mimic the 'CREATE TYPE' in PgAdmin & PgBackup

WITH types AS (
    SELECT n.nspname,
            pg_catalog.format_type ( t.oid, NULL ) AS obj_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 obj_type,
            coalesce ( pg_catalog.obj_description ( t.oid, 'pg_type' ), '' ) AS description
        FROM pg_catalog.pg_type t
        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 n.nspname !~ '^pg_toast'
),
cols AS (
    SELECT n.nspname::text AS schema_name,
            pg_catalog.format_type ( t.oid, NULL ) AS obj_name,
            a.attname::text AS column_name,
            pg_catalog.format_type ( a.atttypid, a.atttypmod ) AS data_type,
            a.attnotnull AS is_required,
            a.attnum AS ordinal_position,
            pg_catalog.col_description ( a.attrelid, a.attnum ) AS description
        FROM pg_catalog.pg_attribute a
        JOIN pg_catalog.pg_type t
            ON a.attrelid = t.typrelid
        JOIN pg_catalog.pg_namespace n
            ON ( n.oid = t.typnamespace )
        JOIN types
            ON ( types.nspname = n.nspname
                AND types.obj_name = pg_catalog.format_type ( t.oid, NULL ) )
        WHERE a.attnum > 0
            AND NOT a.attisdropped
)
SELECT 'CREATE TYPE ' || cols.schema_name || '.' || cols.obj_name || E' AS (\n    ' ||
pg_catalog.array_to_string (ARRAY( 
    SELECT cols.column_name || ' ' || cols.data_type AS col_num_typ
    FROM cols
    WHERE cols.obj_name='my_user_data_type'
    ORDER BY cols.schema_name,
            cols.obj_name,
            cols.ordinal_position ), E',\n    '
    ) || E'\n);'
AS cre_typ
FROM cols
WHERE cols.obj_name='my_user_data_type'
LIMIT 1

and run it under psql with this command to have only the SQL code :

\\t\\a\\g\\a\\t