CREATE DATABASE — create a new database
CREATE DATABASEname[ WITH ] [ OWNER [=]user_name] [ TEMPLATE [=]template] [ ENCODING [=]encoding] [ STRATEGY [=]strategy] ] [ LOCALE [=]locale] [ LC_COLLATE [=]lc_collate] [ LC_CTYPE [=]lc_ctype] [ ICU_LOCALE [=]icu_locale] [ ICU_RULES [=]icu_rules] [ LOCALE_PROVIDER [=]locale_provider] [ COLLATION_VERSION =collation_version] [ TABLESPACE [=]tablespace_name] [ ALLOW_CONNECTIONS [=]allowconn] [ CONNECTION LIMIT [=]connlimit] [ IS_TEMPLATE [=]istemplate] [ OID [=]oid]
CREATE DATABASE creates a new
PostgreSQL database.
To create a database, you must be a superuser or have the special
CREATEDB privilege.
See CREATE ROLE.
By default, the new database will be created by cloning the standard
system database template1. A different template can be
specified by writing TEMPLATE
. In particular,
by writing nameTEMPLATE template0, you can create a pristine
database (one where no user-defined objects exist and where the system
objects have not been altered)
containing only the standard objects predefined by your
version of PostgreSQL. This is useful
if you wish to avoid copying
any installation-local objects that might have been added to
template1.
name #The name of a database to create.
user_name #
The role name of the user who will own the new database,
or DEFAULT to use the default (namely, the
user executing the command). To create a database owned by another
role, you must be able to SET ROLE to that
role.
template #
The name of the template from which to create the new database,
or DEFAULT to use the default template
(template1).
encoding #
Character set encoding to use in the new database. Specify
a string constant (e.g., 'SQL_ASCII'),
or an integer encoding number, or DEFAULT
to use the default encoding (namely, the encoding of the
template database). The character sets supported by the
PostgreSQL server are described in
Section 24.3.1. See below for
additional restrictions.
strategy #
Strategy to be used in creating the new database. If
the WAL_LOG strategy is used, the database will be
copied block by block and each block will be separately written
to the write-ahead log. This is the most efficient strategy in
cases where the template database is small, and therefore it is the
default. The older FILE_COPY strategy is also
available. This strategy writes a small record to the write-ahead log
for each tablespace used by the target database. Each such record
represents copying an entire directory to a new location at the
filesystem level. While this does reduce the write-ahead
log volume substantially, especially if the template database is large,
it also forces the system to perform a checkpoint both before and
after the creation of the new database. In some situations, this may
have a noticeable negative impact on overall system performance.
locale #
Sets the default collation order and character classification in the
new database. Collation affects the sort order applied to strings,
e.g., in queries with ORDER BY, as well as the order used in indexes
on text columns. Character classification affects the categorization
of characters, e.g., lower, upper, and digit. Also sets the
associated aspects of the operating system environment,
LC_COLLATE and LC_CTYPE. The
default is the same setting as the template database. See Section 24.2.2.3.1 and Section 24.2.2.3.2 for details.
Can be overridden by setting lc_collate, lc_ctype, or icu_locale individually.
The other locale settings lc_messages, lc_monetary, lc_numeric, and
lc_time are not fixed per database and are not
set by this command. If you want to make them the default for a
specific database, you can use ALTER DATABASE
... SET.
lc_collate #
Sets LC_COLLATE in the database server's operating
system environment. The default is the setting of locale if specified, otherwise the same
setting as the template database. See below for additional
restrictions.
If locale_provider is
libc, also sets the default collation order to use
in the new database, overriding the setting locale.
lc_ctype #
Sets LC_CTYPE in the database server's operating
system environment. The default is the setting of locale if specified, otherwise the same
setting as the template database. See below for additional
restrictions.
If locale_provider is
libc, also sets the default character
classification to use in the new database, overriding the setting
locale.
icu_locale #
Specifies the ICU locale (see Section 24.2.2.3.2) for the database default
collation order and character classification, overriding the setting
locale. The locale provider must be ICU. The default
is the setting of locale if
specified; otherwise the same setting as the template database.
icu_rules #Specifies additional collation rules to customize the behavior of the default collation of this database. This is supported for ICU only. See Section 24.2.3.4 for details.
locale_provider #
Specifies the provider to use for the default collation in this
database. Possible values are
icu
(if the server was built with ICU support) or libc.
By default, the provider is the same as that of the template. See Section 24.1.4 for details.
collation_version #
Specifies the collation version string to store with the database.
Normally, this should be omitted, which will cause the version to be
computed from the actual version of the database collation as provided
by the operating system. This option is intended to be used by
pg_upgrade for copying the version from an existing
installation.
See also ALTER DATABASE for how to handle database collation version mismatches.
tablespace_name #
The name of the tablespace that will be associated with the
new database, or DEFAULT to use the
template database's tablespace. This
tablespace will be the default tablespace used for objects
created in this database. See
CREATE TABLESPACE
for more information.
allowconn #
If false then no one can connect to this database. The default is
true, allowing connections (except as restricted by other mechanisms,
such as GRANT/REVOKE CONNECT).
connlimit #How many concurrent connections can be made to this database. -1 (the default) means no limit.
istemplate #
If true, then this database can be cloned by any user with CREATEDB
privileges; if false (the default), then only superusers or the owner
of the database can clone it.
oid #The object identifier to be used for the new database. If this parameter is not specified, PostgreSQL will choose a suitable OID automatically. This parameter is primarily intended for internal use by pg_upgrade, and only pg_upgrade can specify a value less than 16384.
Optional parameters can be written in any order, not only the order illustrated above.
CREATE DATABASE cannot be executed inside a transaction
block.
Errors along the line of “could not initialize database directory” are most likely related to insufficient permissions on the data directory, a full disk, or other file system problems.
Use DROP DATABASE to remove a database.
The program createdb is a wrapper program around this command, provided for convenience.
Database-level configuration parameters (set via ALTER DATABASE) and database-level permissions (set via
GRANT) are not copied from the template database.
Although it is possible to copy a database other than template1
by specifying its name as the template, this is not (yet) intended as
a general-purpose “COPY DATABASE” facility.
The principal limitation is that no other sessions can be connected to
the template database while it is being copied. CREATE
DATABASE will fail if any other connection exists when it starts;
otherwise, new connections to the template database are locked out
until CREATE DATABASE completes.
See Section 23.3 for more information.
The character set encoding specified for the new database must be
compatible with the chosen locale settings (LC_COLLATE and
LC_CTYPE). If the locale is C (or equivalently
POSIX), then all encodings are allowed, but for other
locale settings there is only one encoding that will work properly.
(On Windows, however, UTF-8 encoding can be used with any locale.)
CREATE DATABASE will allow superusers to specify
SQL_ASCII encoding regardless of the locale settings,
but this choice is deprecated and may result in misbehavior of
character-string functions if data that is not encoding-compatible
with the locale is stored in the database.
The encoding and locale settings must match those of the template database,
except when template0 is used as template. This is because
other databases might contain data that does not match the specified
encoding, or might contain indexes whose sort ordering is affected by
LC_COLLATE and LC_CTYPE. Copying such data would
result in a database that is corrupt according to the new settings.
template0, however, is known to not contain any data or
indexes that would be affected.
There is currently no option to use a database locale with nondeterministic
comparisons (see CREATE
COLLATION for an explanation). If this is needed, then
per-column collations would need to be used.
The CONNECTION LIMIT option is only enforced approximately;
if two new sessions start at about the same time when just one
connection “slot” remains for the database, it is possible that
both will fail. Also, the limit is not enforced against superusers or
background worker processes.
To create a new database:
CREATE DATABASE lusiadas;
To create a database sales owned by user salesapp
with a default tablespace of salesspace:
CREATE DATABASE sales OWNER salesapp TABLESPACE salesspace;
To create a database music with a different locale:
CREATE DATABASE music
LOCALE 'sv_SE.utf8'
TEMPLATE template0;
In this example, the TEMPLATE template0 clause is required if
the specified locale is different from the one in template1.
(If it is not, then specifying the locale explicitly is redundant.)
To create a database music2 with a different locale and a
different character set encoding:
CREATE DATABASE music2
LOCALE 'sv_SE.iso885915'
ENCODING LATIN9
TEMPLATE template0;
The specified locale and encoding settings must match, or an error will be reported.
Note that locale names are specific to the operating system, so that the above commands might not work in the same way everywhere.
There is no CREATE DATABASE statement in the SQL
standard. Databases are equivalent to catalogs, whose creation is
implementation-defined.