oracle query user permissions

In Oracle database, user permissions refer to permissions that allow or disallow users to perform certain operations. When a user performs certain operations that require special permissions, the system checks whether the user has the corresponding permissions.

Querying user permissions is an important task in managing Oracle databases. Administrators can check the user's permissions to understand what operations the user can perform and how to better manage the database. This article will introduce several methods to query Oracle user permissions.

Method 1: Use the views officially provided by Oracle

Oracle provides some views that can query the permissions of users in the database. Among these views, the most commonly used are the "DBA_SYS_PRIVS" and "DBA_TAB_PRIVS" views.

The DBA_SYS_PRIVS view contains all system-level permission information, including system-level operations, such as creating users, creating roles, modifying parameters, etc. This view has many fields, among which the "GRANTEE" field represents the user who receives these permissions.

To query the system permissions of a user, you can use the following statement:

SELECT * FROM DBA_SYS_PRIVS WHERE GRANTEE = 'username';

The DBA_TAB_PRIVS view contains permission information about tables, views, and sequences. The "GRANTEE" field represents the user who receives these permissions, the "TABLE_SCHEMA" field represents the schema in which the table is located, the "TABLE_NAME" field represents the name of the table, and the "PRIVILEGE" field represents the operations that the user can perform.

To query the permissions of a user on a certain table, you can use the following statement:

SELECT * FROM DBA_TAB_PRIVS WHERE GRANTEE = 'username' AND TABLE_SCHEMA = 'schema_name' AND TABLE_NAME = 'table_name';

Method 2: Use the USER_SYS_PRIVS and USER_TAB_PRIVS views

In addition to the DBA_SYS_PRIVS and DBA_TAB_PRIVS views , Oracle also provides USER_SYS_PRIVS and USER_TAB_PRIVS views for querying the system and table-level permissions of the current user.

To query the current user's system permissions, you can use the following statement:

SELECT * FROM USER_SYS_PRIVS;

To query the current user's permissions on a certain table, you can use the following statement:

SELECT * FROM USER_TAB_PRIVS WHERE TABLE_NAME = 'table_name';

Method 3 : Use the V$SESSION view

The V$SESSION view contains information about all current sessions, including permission information for each user. By querying this view, you can obtain the permission information of the current user.

To query the permissions of the current user, you can use the following statement:

SELECT * FROM V$SESSION WHERE AUDSID = USERENV('SESSIONID');

This statement will return information related to the permissions of the current user, including user name, role, permission name, etc.

Method 4: Use PL/SQL statements

The last method is to use PL/SQL statements to query user permissions. The following is an example of querying all permissions of a user:

DECLARE
    v_count NUMBER;
BEGIN
    SELECT COUNT(*) INTO v_count FROM DBA_SYS_PRIVS WHERE GRANTEE = 'username';
    IF v_count > 0 THEN
        DBMS_OUTPUT.PUT_LINE('System privileges:');
        FOR i IN (SELECT * FROM DBA_SYS_PRIVS WHERE GRANTEE = 'username' ORDER BY PRIVILEGE) LOOP
            DBMS_OUTPUT.PUT_LINE(i.PRIVILEGE);
        END LOOP;
    END IF;

    SELECT COUNT(*) INTO v_count FROM DBA_TAB_PRIVS WHERE GRANTEE = 'username';
    IF v_count > 0 THEN
        DBMS_OUTPUT.PUT_LINE('Table privileges:');
        FOR i IN (SELECT * FROM DBA_TAB_PRIVS WHERE GRANTEE = 'username' ORDER BY TABLE_NAME, PRIVILEGE) LOOP
            DBMS_OUTPUT.PUT_LINE(i.TABLE_NAME || ' ' || i.PRIVILEGE);
        END LOOP;
    END IF;
END;

This PL/SQL program will query the user's system and table permissions and output the results to the console.

Conclusion

Querying the permissions of Oracle users is one of the skills that database administrators and developers must master. By using the above methods, users' permissions can be easily queried and the database can be better managed and optimized.

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