PG_DATABASE

oid

oid

Row identifier (hidden attribute, which must be specified)

datname

name

Database name

datdba

oid

Owner of the database, usually the user who created it

encoding

integer

Character encoding for the database

datcollate

name

Sequence used by the database

datctype

name

Character type used by the database

datistemplate

boolean

Whether the database can be used as a template database

• true: allowed.
• false: not allowed.

datallowconn

boolean

If the value is true, users can connect to the database. If the value is false, no one can connect to this database. This column is used to protect the template0 database from being altered.

datconnlimit

integer

Maximum number of concurrent connections allowed on this database. The value -1 indicates no limit.

datlastsysoid

oid

Last system OID in the database

datfrozenxid

xid32

Tracks whether the database needs to be vacuumed to prevent transaction ID wraparound. This column is discarded in the current version. To ensure forward compatibility, this column is reserved. The datfrozenxid64 column is added to record the information.

dattablespace

oid

Default tablespace of the database

datcompatibility

name

Database compatibility mode Currently, four compatible modes are supported: PG, ORA, MYSQL, and TD.

datacl

aclitem[]

Access permission

datfrozenxid64

xid

Tracks whether the database needs to be vacuumed to prevent transaction ID wraparound.

datminmxid

xid

All multi-transaction IDs before this one have been replaced with a transaction ID in the database. This is used to track whether the database needs to be vacuumed in order to prevent transaction ID wraparound or to allow pg_clog to be shrunk. It is the minimum value of pg_class.relminmxid of all tables in the database.