The catalog pg_foreign_data_wrapper stores foreign-data wrapper definitions. A foreign-data wrapper is the mechanism by which external data

The catalog pg_type stores information about data types. Base types and enum types (scalar types) are created with

The view pg_shadow exists for backwards compatibility: it emulates a catalog that existed in PostgreSQL before

The catalog pg_shdescription stores optional descriptions (comments) for shared database objects. Descriptions can be manipulated with the

The pg_available_extension_versions view lists the specific extension versions that are available for installation. See also the

The view pg_policies provides access to useful information about each row-level security policy in the database.

The catalog pg_proc stores information about functions (or procedures). See

The catalog pg_default_acl stores initial privileges to be assigned to newly created objects.

The view pg_roles provides access to information about database roles. This is simply a publicly readable view of

The catalog pg_conversion describes encoding conversion procedures. See