历史版本。 PostgreSQL 9.2 已结束支持。 2017-11-09. 请参阅 当前版本手册.
45.15. pg_database #
目录pg_database存储有关可用数据库的信息。数据库通过CREATE DATABASE命令创建。更多关于其参数的信息请查阅第 21 章。
和大部分系统目录不同，pg_database是在集簇的所有数据库之间共享的：在一个集簇中只有一份pg_database拷贝，而不是每个数据库一份。
表 45.15. pg_database 列
| Name | Type | References | Description |
|---|---|---|---|
datname | name | Database name | |
datdba | oid | | Owner of the database, usually the user who created it |
encoding | int4 | 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 | bool | 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 | bool | If false then no one can connect to this database. This is
used to protect the template0 database from being altered.
| |
datconnlimit | int4 | Sets maximum number of concurrent connections that can be made to this database. -1 means no limit. | |
datlastsysoid | oid | Last system OID in the database; useful particularly to pg_dump | |
datfrozenxid | xid | All transaction IDs before this one have been replaced with a permanent
(“frozen”) transaction ID in this 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 of the per-table
pg_class.relfrozenxid values.
| |
dattablespace | 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; in particular, all the non-shared
system catalogs will be there.
|
datacl | aclitem[] | Access privileges; see GRANT and REVOKE for details |