NAME

ALTER USER - 改變數據庫用戶帳號

SYNOPSIS

ALTER USER name [ [ WITH ] option [ ... ] ]

where option can be:

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

ALTER USER name RENAME TO newname

ALTER USER name SET parameter { TO | = } { value | DEFAULT }
ALTER USER name RESET parameter

DESCRIPTION 描述

ALTER USER 用于更改用戶的 PostgreSQL 帳號的屬性。 沒有在該命令中出現的屬性保持原值。

 這條命令模式中的***個變種修改某些全局用戶權限和認證設置。 （見下文獲取細節。）只有數據庫超級用戶可以用這條命令改變這些權限和使口令失效。普通用戶只能修改它們自己的口令。

 第二個變種改變用戶的名字。只有數據庫超級用戶才能重新命名用戶帳戶。 當前會話用戶不能重命名。（如果想這么干，先用另外一個用戶賬號連接。）

 第三和第四個變種修改用戶會話的特定配置變量的缺省值。 當該用戶隨后啟動一個新的會話時，聲明的數值將成為會話的缺省，覆蓋 任何出現在 postgresql.conf 里，或者從 postmaster  命令行接收到的設置。 普通用戶可以修改它們自己的會話缺省。超級用戶可以修改任何用戶的缺省。  

PARAMETERS 參數

name

 想進行屬性更改的用戶名字。

password

 此帳號所使用的新口令。

ENCRYPTED

UNENCRYPTED

 這些關鍵字控制口令是否以加密形式存在 pg_shadow 里。 （參閱 CREATE USER [create_user(7)] 獲取這個選項的更多信息。）

CREATEDB

NOCREATEDB

 這個子句定義該用戶創建數據庫的能力。 如果聲明了CREATEDB，該用戶可以創建她自己的數據庫。 用NOCREATEDB將剝奪一個用戶創建數據庫的能力。

CREATEUSER

NOCREATEUSER

 這個子句決定一個用戶能否創建新用戶。 這個選項同樣還令該用戶成為超級用戶，可以超越所有訪問限制。

abstime

 該用戶帳號口令的過期的日期（和可選的時間）。 要設置一個口令從不過期，可以用'infinity'。

newname

 用戶的新名字。

parameter

value

 把該用戶特定的配置變量的會話缺省設置為給定的數值。 如果 value 為 DEFAULT  或者使用了等效的 RESET，那么刪除用戶相關的變量， 并且該用戶將在新會話中繼承缺省設置。使用 RESET ALL  清除所有設置。

 參閱 SET [set(7)] 和 Section 16.4 ``Run-time Configuration'' 獲取有關可用變量和數值的更多信息。

NOTES 注意

 使用 CREATE USER [create_user(7)] 創建新用戶和 DROP USER [drop_user(7)] 刪除用戶。

ALTER USER 無法改變一個用戶的組的成員性。 用 ALTER GROUP [alter_group(7)] 實現這個目地。

 使用 ALTER DATABASE [alter_database(7)]，我們還可能把一個會話缺省和某個數據庫綁定起來，而不是和某個用戶綁定。  

EXAMPLES 例子

 更改一用戶口令：

ALTER USER davide WITH PASSWORD 'hu8jmn3';

 更改一用戶有效期：

ALTER USER manuel VALID UNTIL 'Jan 31 2030';

 更改一用戶有效期， 聲明其權限應該在用比UTC早一小時的時區記時的 2005 年 5 月 4 日正午失效

ALTER USER chris VALID UNTIL 'May 4 12:00:00 2005 +1';

 令用戶永遠有效：

ALTER USER fred VALID UNTIL 'infinity';

 賦予一用戶創建新用戶和新數據庫的權限：

ALTER USER miriam CREATEUSER CREATEDB;

COMPATIBILITY 兼容性

ALTER USER 語句是 PostgreSQL 擴展。SQL 標準將用戶的定義交給實現完成。  

SEE ALSO 參見

CREATE USER [create_user(7)], DROP USER [drop_user(l)], SET [set(l)]

#p#

NAME

ALTER USER - change a database user account

SYNOPSIS

ALTER USER name [ [ WITH ] option [ ... ] ]

where option can be:

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

ALTER USER name RENAME TO newname

ALTER USER name SET parameter { TO | = } { value | DEFAULT }
ALTER USER name RESET parameter

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 these privileges and the password expiration with this command. Ordinary users can only change their own password.

The second variant changes the name of the user. Only a database superuser can rename user accounts. The session user cannot be renamed. (Connect as a different user if you need to do that.)

The third and the fourth 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 command line. Ordinary users can change their own session defaults. Superusers can change anyone's session defaults.  

PARAMETERS

name

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 [create_user(7)] for more information about this choice.)

CREATEDB

NOCREATEDB

These clauses define a user's ability to create databases. If CREATEDB is specified, the user 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. To set the password never to expire, use 'infinity'.

newname

The new name of the user.

parameter

value

Set this user's session default for the specified configuration parameter 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 [set(7)] and the section called ``Run-time Configuration'' in the documentation for more information about allowed parameter names and values.

NOTES

Use CREATE USER [create_user(7)] to add new users, and DROP USER [drop_user(7)] to remove a user.

ALTER USER cannot change a user's group memberships. Use ALTER GROUP [alter_group(7)] to do that.

Using ALTER DATABASE [alter_database(7)], 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 2005 using the time zone which is one hour ahead of UTC:

ALTER USER chris VALID UNTIL 'May 4 12:00:00 2005 +1';

Make a user valid forever:

ALTER USER fred VALID UNTIL 'infinity';

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 [create_user(7)], DROP USER [drop_user(l)], SET [set(l)]