PostgreSQL 7.3.4 Documentation
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# ALTER USER

## Name

ALTER USER -- change a database user account

## Synopsis

    ALTER USER username [ [ WITH ] option [ ... ] ]

    where option can be:

          [ ENCRYPTED | UNENCRYPTED ] PASSWORD 'password'
        | CREATEDB | NOCREATEDB
        | CREATEUSER | NOCREATEUSER
        | VALID UNTIL 'abstime'

    ALTER USER username SET variable { TO | = } { value | DEFAULT }
    ALTER USER username RESET variable

## Description

`ALTER USER` is used to change the attributes of a PostgreSQL user account. Attributes not mentioned in the command retain their previous settings.

The first variant of this command in the synopsis changes certain global user privileges and authentication settings. (See below for details.) Only a database superuser can change privileges and password expiration with this command. Ordinary users can only change their own password.

The second and the third variant change a user's session default for a specified configuration variable. Whenever the user subsequently starts a new session, the specified value becomes the session default, overriding whatever setting is present in `postgresql.conf` or has been received from the postmaster. Ordinary users can change their own session defaults. Superusers can change anyone's session defaults.

### Parameters

username

  The name of the user whose attributes are to be altered.

password

  The new password to be used for this account.

ENCRYPTED
UNENCRYPTED

  These key words control whether the password is stored encrypted in pg_shadow. (See CREATE USER for more information about this choice.)

CREATEDB
NOCREATEDB

  These clauses define a user's ability to create databases. If CREATEDB is specified, the user being defined will be allowed to create his own databases. Using NOCREATEDB will deny a user the ability to create databases.

CREATEUSER
NOCREATEUSER

  These clauses determine whether a user will be permitted to create new users himself. This option will also make the user a superuser who can override all access restrictions.

abstime

  The date (and, optionally, the time) at which this user's password is to expire.

variable
value

  Set this user's session default for the specified configuration variable to the given value. If value is DEFAULT or, equivalently, RESET is used, the user-specific variable setting is removed and the user will inherit the system-wide default setting in new sessions. Use RESET ALL to clear all settings.

  See SET and the Administrator's Guide for more information about allowed variable names and values.

## Diagnostics

`ALTER USER`

  Message returned if the alteration was successful.

`ERROR: ALTER USER: user "username" does not exist`

  Error message returned if the specified user is not known to the database.

## Notes

Use CREATE USER to add new users, and DROP USER to remove a user.

`ALTER USER` cannot change a user's group memberships. Use ALTER GROUP to do that.

Using ALTER DATABASE, it is also possible to tie a session default to a specific database rather than a user.

## Examples

Change a user password:

    ALTER USER davide WITH PASSWORD 'hu8jmn3';

Change a user's valid until date:

    ALTER USER manuel VALID UNTIL 'Jan 31 2030';

Change a user's valid until date, specifying that his authorization should expire at midday on 4th May 1998 using the time zone which is one hour ahead of UTC:

    ALTER USER chris VALID UNTIL 'May 4 12:00:00 1998 +1';

Give a user the ability to create other users and new databases:

    ALTER USER miriam CREATEUSER CREATEDB;

## Compatibility

The `ALTER USER` statement is a PostgreSQL extension. The SQL standard leaves the definition of users to the implementation.

## See Also

CREATE USER, DROP USER, SET

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