Contents
pg_collation_is_visible()
A function for determining whether a collation is visible in the current search path
pg_collation_is_visible() is a system function for determining whether a collation is visible in the current schema search path.
pg_collation_is_visible() was added in PostgreSQL 9.1.
Usage
pg_collation_is_visible (collationoid) →boolean
The collation parameter can be provided as a text value with the regcollation OID alias containing the collation's name. In this case the name should be provided as a schema-qualified value (e.g. "someschema.somecollation"), otherwise an ERROR will be raised if the collation exists but is not visible in the current search path.
Change history
- PostgreSQL 9.1
- added (commit 414c5a2e)
Examples
Example usage for pg_collation_is_visible(), assuming the following collation has been created:
postgres=# CREATE COLLATION collations.british_english (locale = 'en_GB.utf8'); CREATE COLLATION
dads
postgres=# SHOW search_path; search_path ----------------- "$user", public (1 row) postgres=# SELECT pg_collation_is_visible('collations.british_english'); ERROR: invalid input syntax for type oid: "collations.british_english" LINE 1: SELECT pg_collation_is_visible('collations.british_english')... postgres=# SET search_path TO public, collations; SET postgres=# SELECT pg_collation_is_visible('collations.british_english'::regcollation); pg_collation_is_visible ------------------------- t (1 row)
An ERROR will be raised if the collation does not exist, or exists but is not schema-qualified and not in the current search path:
postgres=# SELECT pg_collation_is_visible('collations.foo'::regcollation);
ERROR: collation "collations.foo" for encoding "UTF8" does not exist
LINE 1: SELECT pg_collation_is_visible('collations.foo'::regcollatio...
postgres=# SHOW search_path;
search_path
-----------------
"$user", public
(1 row)
postgres=# SELECT pg_collation_is_visible('british_english'::regcollation);
ERROR: collation "british_english" for encoding "UTF8" does not exist
LINE 1: SELECT pg_collation_is_visible('british_english'::regcollati...
References
- PostgreSQL documentation: pg_collation_is_visible()