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CREATE DATABASE

Name

CREATE DATABASE  --  Creates a new database

Synopsis

CREATE DATABASE name
    [ WITH [ LOCATION = 'dbpath' ]
           [ TEMPLATE = template ]
           [ ENCODING = encoding ] ]
  

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.

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 CREATE USER.

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.

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 initlocation 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.

Notes

CREATE DATABASE is a Postgres language extension.

Use DROP DATABASE to remove a database.

The program createdb 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.

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

SQL92

There is no CREATE DATABASE statement in SQL92. Databases are equivalent to catalogs whose creation is implementation-defined.

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