PostgreSQL 8.2.13 Documentation
Prev | Fast Backward | Chapter 5. Data Definition | Fast Forward | Next

# 5.6. Privileges

When you create a database object, you become its owner. By default, only the owner of an object can do anything with the object. In order to allow other users to use it, privileges must be granted. (However, users that have the superuser attribute can always access any object.)

There are several different privileges: `SELECT`, `INSERT`, `UPDATE`, `DELETE`, `REFERENCES`, `TRIGGER`, `CREATE`, `CONNECT`, `TEMPORARY`, `EXECUTE`, and `USAGE`. The privileges applicable to a particular object vary depending on the object's type (table, function, etc). For complete information on the different types of privileges supported by PostgreSQL, refer to the GRANT reference page. The following sections and chapters will also show you how those privileges are used.

The right to modify or destroy an object is always the privilege of the owner only.

> Note: To change the owner of a table, index, sequence, or view, use the ALTER TABLE command. There are corresponding `ALTER` commands for other object types.

To assign privileges, the `GRANT` command is used. For example, if `joe` is an existing user, and `accounts` is an existing table, the privilege to update the table can be granted with

    GRANT UPDATE ON accounts TO joe;

Writing `ALL` in place of a specific privilege grants all privileges that are relevant for the object type.

The special "user" name `PUBLIC` can be used to grant a privilege to every user on the system. Also, "group" roles can be set up to help manage privileges when there are many users of a database — for details see Chapter 18.

To revoke a privilege, use the fittingly named `REVOKE` command:

    REVOKE ALL ON accounts FROM PUBLIC;

The special privileges of the object owner (i.e., the right to do `DROP`, `GRANT`, `REVOKE`, etc.) are always implicit in being the owner, and cannot be granted or revoked. But the object owner can choose to revoke his own ordinary privileges, for example to make a table read-only for himself as well as others.

Ordinarily, only the object's owner (or a superuser) can grant or revoke privileges on an object. However, it is possible to grant a privilege "with grant option", which gives the recipient the right to grant it in turn to others. If the grant option is subsequently revoked then all who received the privilege from that recipient (directly or through a chain of grants) will lose the privilege. For details see the GRANT and REVOKE reference pages.

Prev | Home | Next
Modifying Tables | Up | Schemas