pg_database

The pg_database system catalog table stores information about the available databases. Databases are created with the CREATE DATABASE SQL command. Unlike most system catalogs, pg_database is shared across all databases in the system. There is only one copy of pg_database per system, not one per database.

column	type	references	description
oid	oid		The object ID
datname	name		Database name
datdba	oid	pg_authid.oid	Owner of the database, usually the user who created it
encoding	integer		Character encoding for this database. pg_encoding_to_char() can translate this number to the encoding name
datcollate	name		LC_COLLATE for this database
datctype	name		LC_CTYPE for this database
datistemplate	boolean		If true then this database can be used in the TEMPLATE clause of CREATE DATABASE to create a new database as a clone of this one
datallowconn	boolean		If false then no one can connect to this database. This is used to protect the template0 database from being altered
datconnlimit	integer		Sets the maximum number of concurrent connections that can be made to this database. -1 means no limit
datlastsysoid	oid		Last system OID in the database
datfrozenxid	xid		Deprecated
datminmxid	xid		Deprecated
dattablespace	oid	pg_tablespace.oid	The default tablespace for the database. Within this database, all tables for which pg_class.reltablespace is zero will be stored in this tablespace. All non-shared system catalogs will also be there
datacl	aclitem[]		Database access privileges as given by GRANT and REVOKE
datdefaultts	oid	pg_tablespace.oid	Default table space for creating table in this DB