CREATE DATABASE
SQL - Language Statements
CREATE DATABASE
Creates a new database
1999-12-11
CREATE DATABASE name
[ WITH [ LOCATION = 'dbpath' ]
[ TEMPLATE = template ]
[ ENCODING = encoding ] ]
1999-12-11
Inputs
name
The name of a database to create.
dbpath
An alternate filesystem location in which to store the new database,
specified as a string literal;
or DEFAULT to use the default location.
template
Name of template from which to create the new database,
or DEFAULT to use the default template
(template1).
encoding
Multibyte encoding method to use in the new database. Specify
a string literal name (e.g., 'SQL_ASCII'),
or an integer encoding number, or DEFAULT
to use the default encoding.
1999-12-11
Outputs
CREATE DATABASE
Message returned if the command completes successfully.
ERROR: user 'username' is not allowed to create/drop databases
You must have the special CREATEDB privilege to create databases.
See .
ERROR: createdb: database "name" already exists
This occurs if a database with the name
specified already exists.
ERROR: database path may not contain single quotes
The database location
dbpath cannot contain
single quotes. This is required so that the shell commands that
create the database directory can execute safely.
ERROR: CREATE DATABASE: may not be called in a transaction block
If you have an explicit transaction block in progress you cannot call
CREATE DATABASE. You must finish the transaction first.
ERROR: Unable to create database directory 'path'.
ERROR: Could not initialize database directory.
These are most likely related to insufficient permissions on the data
directory, a full disk, or other file system problems. The user under
which the database server is running must have access to the location.
1999-12-11
Description
CREATE DATABASE creates a new
Postgres database.
The creator becomes the owner of the new database.
An alternate location can be specified in order to,
for example, store the database on a different disk.
The path must have been prepared with the
command.
If the path name does not contain a slash, it is interpreted
as an environment variable name, which must be known to the
server process. This way the database administrator can
exercise control over locations in which databases can be created.
(A customary choice is, e.g., 'PGDATA2'.)
If the server is compiled with ALLOW_ABSOLUTE_DBPATHS
(not so by default), absolute path names, as identified by
a leading slash
(e.g., '/usr/local/pgsql/data'),
are allowed as well.
By default, the new database will be created by cloning the standard
system database template1>. A different template can be
specified by writing TEMPLATE =>
name. In particular,
by writing TEMPLATE = template0>, you can create a virgin
database containing only the standard objects predefined by your
version of Postgres. This is useful if you wish to avoid copying
any installation-local objects that may have been added to template1.
The optional encoding parameter allows selection of the database encoding,
if your server was compiled with multibyte encoding support. When not
specified, it defaults to the encoding used by the selected template
database.
Optional parameters can be written in any order, not only the order
illustrated above.
1999-12-11
Notes
CREATE DATABASE is a Postgres
language extension.
Use to remove a database.
The program is a
shell script wrapper around this command, provided for convenience.
There are security and data integrity issues
involved with using alternate database locations
specified with absolute path names, and by default
only an environment variable known to the backend may be
specified for an alternate location.
See the Administrator's Guide for more information.
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. In particular, it is
essential that the source database be idle (no data-altering transactions
in progress)
for the duration of the copying operation. CREATE DATABASE will check
that no backend processes (other than itself) are connected to
the source database at the start of the operation, but this does not
guarantee that changes cannot be made while the copy proceeds. Therefore,
we recommend that databases used as templates be treated as read-only.
Two useful flags exist in pg_database for each
database: datistemplate and
datallowconn. datistemplate
may be set to indicate that a database is intended as a template for
CREATE DATABASE. If this flag is set, the database may be cloned by
any user with CREATEDB privileges; if it is not set, only superusers
and the owner of the database may clone it.
If datallowconn is false, then no new connections
to that database will be allowed (but existing sessions are not killed
simply by setting the flag false). The template0
database is normally marked this way to prevent modification of it.
After preparing a template database, or making any changes to one,
it is a good idea to perform
VACUUM FREEZE> or VACUUM FULL FREEZE> in that
database. If this is done when there are no other open transactions
in the same database, then it is guaranteed that all tuples in the
database are frozen> and will not be subject to transaction
ID wraparound problems. This is particularly important for a database
that will have datallowconn set to false, since it
will be impossible to do routine maintenance VACUUM>s on
such a database.
See the Administrator's Guide for more information.
Usage
To create a new database:
olly=> create database lusiadas;
To create a new database in an alternate area ~/private_db:
$ mkdir private_db
$ initlocation ~/private_db
Creating Postgres database system directory /home/olly/private_db/base
$ psql olly
Welcome to psql, the PostgreSQL interactive terminal.
Type: \copyright for distribution terms
\h for help with SQL commands
\? for help on internal slash commands
\g or terminate with semicolon to execute query
\q to quit
olly=> CREATE DATABASE elsewhere WITH LOCATION = '/home/olly/private_db';
CREATE DATABASE
Compatibility
1998-04-15
SQL92
There is no CREATE DATABASE statement in SQL92.
Databases are equivalent to catalogs whose creation is implementation-defined.