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Don Burleson Blog

Oracle Concepts - Drop Users System and Object Privileges

Oracle Tips by Burleson Consulting

Dropping Users

To drop a user, you must have the DROP USER system privilege. You can drop users with Server Manager or at the command line in SQL*Plus. The command line syntax for dropping a user is illustrated in Listing 36.

Listing 36: DROP USER Command

Here is an example:

DROP USER edward CASCADE;

If a user owns any database objects, you can only drop that user by including the CASCADE keyword in the DROP USER command. The DROP USER command with the CASCADE keyword drops the user and all objects owned by that user. If you are using Server Manager to drop a user, you need to indicate that the associated schema objects be included in the command to drop the user. If a user owns objects and you fail to include CASCADE, you will receive an error message and the user will not be dropped. If a user is currently connected to the database, you cannot drop that user until he exits. After a user is dropped, all information on that user and all objects owned by that user are removed from the database.

After you have issued the command to drop a user, you cannot perform a rollback to re-create the user and his objects. DROP USER is a DDL command, which cannot be rolled back.

If you need the objects created by that user, you can revoke the CREATE SESSION system privilege to prevent the user from logging on, instead of dropping the user. You can also copy the objects to another user by importing the objects from an export made before the user was dropped. To avoid the problem of dropping a user without losing your application tables, all application tables should be owned by a separate application schema instead of an actual database user schema.

Grants

There are two types of (grants) privileges that can be granted:

* System privileges

* Object privileges

System privileges enable a user to perform a particular systemwide action or to perform a particular action on a particular type of object. For example, the privilege to create a table (CREATE TABLE) or insert rows into any table (INSERT ANY TABLE) are system privileges.

Object privileges enable a user to perform a particular action on a specific object, including tables, views, sequences, procedures, functions, and packages. For example, the privilege to insert rows into a particular table is an object privilege. Object privilege grants always include the name of the object for which the privilege is granted. Object privileges extend down to the level of individual columns in a table. These privileges are discussed in the following sections.

System Privileges

All users require the CREATE SESSION privilege to access the database. This privilege is automatically granted to all users when you perform the grants using Server Manager. If you create the user in command line mode, you must remember to explicitly grant each user the CREATE SESSION system privilege either directly or through a role. Listing 36 shows the syntax for the GRANT command. Here is an example of the command used to grant CREATE SESSION and CREATE TABLE.

GRANT create session, create table
TO annie
WITH ADMIN OPTION;

Listing 36: The syntax for GRANT command

System privileges also include roles that have been created.

System privileges can be granted to other users when the grant made includes the WITH ADMIN OPTION.

There are over 80 distinct privileges. Most of these are self-explanatory. Table 13 lists of all the system privileges, as listed in RevealNet's Oracle Administration product (used with their permission).

Privilege

Description

System Privilege

Allows grantee to . . .

FOR CLUSTERS:

Privilege	Description
CREATE CLUSTER	Create clusters in grantee's schema.
CREATE ANY CLUSTER	Create a cluster in any schema except SYS. Behaves similarly to CREATE ANY TABLE.
ALTER ANY CLUSTER	Alter clusters in any schema except SYS.
DROP ANY CLUSTER	Drop clusters in any schema except SYS.

FOR CONTEXTS:

Privilege	Description
CREATE ANY CONTEXT	Create any context namespace.
DROP ANY CONTEXT	Drop any context namespace.

FOR DATABASE:

Privilege	Description
ALTER DATABASE	Alter the database.
ALTER SYSTEM	Issue ALTER SYSTEM statements.
AUDIT SYSTEM	Issue AUDIT sql_statements statements.

FOR DATABASE LINKS:

Privilege	Description
CREATE DATABASE LINK	Create private database links in grantee's schema.
CREATE PUBLIC DATABASE LINK	Create public database links.
DROP PUBLIC DATABASE LINK	Drop public database links.

FOR DIRECTORIES :

Privilege	Description
CREATE ANY DIRECTORY	Create directory database objects.
DROP ANY DIRECTORY	Drop directory database objects.

FOR INDEXES:

Privilege	Description
CREATE INDEX	Create in the grantee's schema an index on any table in the grantee's schema or a domain index.
CREATE ANY INDEX	Create in any schema except SYS a domain index or an index on any table in any schema except SYS.
ALTER ANY INDEX	Alter indexes in any schema except SYS.
DROP ANY INDEX	Drop indexes in any schema except SYS.

FOR LIBRARIES:

Privilege	Description
CREATE LIBRARY	Create external procedure/function libraries in grantee's schema.
CREATE ANY LIBRARY	Create external procedure/function libraries in any schema except SYS.
DROP LIBRARY	Drop external procedure/function libraries in the grantee's schema.
DROP ANY LIBRARY	Drop external procedure/function libraries in any schema except SYS.

FOR PROCEDURES :

Privilege	Description
CREATE PROCEDURE	Create stored procedures, functions, and packages in grantee's schema
CREATE ANY PROCEDURE	Create stored procedures, functions, and packages in any schema except SYS.
ALTER ANY PROCEDURE	Alter stored procedures, functions, or packages in any schema except SYS
DROP ANY PROCEDURE	Drop stored procedures, functions, or packages in any schema except SYS
EXECUTE ANY PROCEDURE	Execute procedures or functions (standalone or packaged) Reference public package variables in any schema except SYS

FOR PROFILES:

Privilege	Description
CREATE PROFILE	Create profiles
ALTER PROFILE	Alter profiles
DROP PROFILE	Drop profiles

FOR ROLES:

Privilege	Description
CREATE ROLE	Create roles
ALTER ANY ROLE	Alter any role in the database
DROP ANY ROLE	Drop roles
GRANT ANY ROLE	Grant any role in the database

FOR ROLLBACK SEGMENTS:

Privilege	Description
CREATE ROLLBACK SEGMENT	Create rollback segments
ALTER ROLLBACK SEGMENT	Alter rollback segments
DROP ROLLBACK SEGMENT	Drop rollback segments

FOR SEQUENCES:

Privilege	Description
CREATE SEQUENCE	Create sequences in grantee's schema
CREATE ANY SEQUENCE	Create sequences in any schema except SYS
ALTER ANY SEQUENCE	Alter any sequence in the database
DROP ANY SEQUENCE	Drop sequences in any schema except SYS
SELECT ANY SEQUENCE	Reference sequences in any schema except SYS

FOR SESSIONS:

Privilege	Description
CREATE SESSION	Connect to the database
ALTER RESOURCE COST	Set costs for session resources
ALTER SESSION	Issue ALTER SESSION statements
RESTRICTED SESSION	Logon after the instance is started using the SQL*Plus STARTUP RESTRICT statement

FOR SNAPSHOTS:

Privilege	Description
CREATE SNAPSHOT	Create snapshots in grantee's schema
CREATE ANY SNAPSHOT	Create snapshots in any schema except SYS
ALTER ANY SNAPSHOT	Alter any snapshot in the database
DROP ANY SNAPSHOT	Drop snapshots in any schema except SYS

FOR SYNONYMS:

Privilege	Description
CREATE SYNONYM	Create synonyms in grantee's schema
CREATE ANY SYNONYM	Create private synonyms in any schema except SYS
CREATE PUBLIC SYNONYM	Create public synonyms
DROP ANY SYNONYM	Drop private synonyms in any schema except SYS
DROP PUBLIC SYNONYM	Drop public synonyms

FOR TABLES:

Privilege	Description
CREATE ANY TABLE	Create tables in any schema except SYS. The owner of the schema containing the table must have space quota on the tablespace to contain the table.
ALTER ANY TABLE	Alter any table or view in the schema
BACKUP ANY TABLE	Use the Export utility to incrementally export objects from the schema of other users
DELETE ANY TABLE	Delete rows from tables, table partitions, or views in any schema except SYS
DROP ANY TABLE	Drop or truncate tables or table partitions in any schema except SYS
INSERT ANY TABLE	Insert rows into tables and views in any schema except SYS
LOCK ANY TABLE	Lock tables and views in any schema except SYS
UPDATE ANY TABLE	Update rows in tables and views in any schema except SYS
SELECT ANY TABLE	Query tables, views, or snapshots in any schema except SYS

FOR TABLESPACES:

Privilege	Description
CREATE TABLESPACE	Create tablespaces
ALTER TABLESPACE	Alter tablespaces
DROP TABLESPACE	Drop tablespaces
MANAGE TABLESPACE	Take tablespaces offline and online and begin and end tablespace backups

This is an excerpt from the eBook "Oracle DBA made Simple".

For more details on Oracle database administration, see the "Easy Oracle Jumpstart" by Robert Freeman and Steve Karam. It?s only $19.95 when you buy it directly from the publisher here.

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