Contents
pg_function_is_visible()
pg_function_is_visible() is a system function for determining whether a function or procedure is visible in the current schema search path.
pg_function_is_visible() was added in PostgreSQL 7.3.
Usage
pg_function_is_visible (functionoid) →boolean
The function parameter can be provided as a text value with the regproc or regprocedure OID alias containing the function's name. In this case the name should be provided as a schema-qualified value (e.g. "someschema.somefunction"), otherwise an ERROR will be raised if the function exists but is not visible in the current search path.
Change history
- PostgreSQL 7.3
- added (commit 4ab8e690)
Examples
Example usage for pg_function_is_visible(), assuming the hstore extension has been installed into the hstore schema:
postgres=# CREATE EXTENSION hstore WITH SCHEMA hstore ; CREATE EXTENSION postgres=# SHOW search_path; search_path ----------------- "$user", public (1 row) postgres=# SELECT hstore(ROW(1,2)); ERROR: function hstore(record) does not exist LINE 1: SELECT hstore(ROW(1,2)); ^ HINT: No function matches the given name and argument types. You might need to add explicit type casts. postgres=# SELECT hstore.hstore(ROW(1,2)); hstore ---------------------- "f1"=>"1", "f2"=>"2" (1 row) postgres=# SELECT pg_function_is_visible('hstore.hstore(record)'::regprocedure); pg_function_is_visible ------------------------ f (1 row) postgres=# SET search_path TO public,hstore; SET postgres=# SELECT pg_function_is_visible('hstore.hstore(record)'::regprocedure); pg_function_is_visible ------------------------ t (1 row)
An ERROR will be raised if the function does not exist, or exists but is not schema-qualified and not in the current search path:
postgres=# SELECT pg_function_is_visible('foo'::regproc);
ERROR: function "foo" does not exist
LINE 1: SELECT pg_function_is_visible('foo'::regproc);
postgres=# SHOW search_path;
search_path
-----------------
"$user", public
(1 row)
postgres=# SELECT pg_function_is_visible('hstore(record)'::regprocedure);
ERROR: function "hstore(record)" does not exist
LINE 1: SELECT pg_function_is_visible('hstore(record)'::regprocedure...
References
- PostgreSQL documentation: Schema Visibility Inquiry Functions,