View Privileges in the Data Dictionary
Overview:
View privileges refer to the permissions associated with accessing, creating, or manipulating views in a database. The data dictionary contains information about these privileges, allowing administrators to review and manage access control.
Key Components:
Data Dictionary Views for Privileges:
Different SQL database management systems (DBMS) provide data dictionary views or tables to access information about object privileges. These views typically include details on which users or roles have specific privileges on views.
Common Data Dictionary Views:
Oracle: ALL_TAB_PRIVS, DBA_TAB_PRIVS, USER_TAB_PRIVS
MySQL: INFORMATION_SCHEMA.TABLE_PRIVILEGES, INFORMATION_SCHEMA.VIEW_TABLE_USAGE
SQL Server: sys.database_permissions, sys.objects, sys.database_principals
Examples of Data Dictionary Views:
Oracle Data Dictionary Views:
ALL_TAB_PRIVS: Provides information about the privileges granted on tables and views that the current user has access to.
-- Query to find privileges on views accessible by the current user SELECT * FROM ALL_TAB_PRIVS WHERE TABLE_NAME = 'VIEW_NAME' AND TABLE_OWNER = 'SCHEMA_NAME';
DBA_TAB_PRIVS: Provides similar information but is accessible to users with DBA privileges. It lists privileges for all users across the database.
-- Query to find privileges on a view across the database SELECT * FROM DBA_TAB_PRIVS WHERE TABLE_NAME = 'VIEW_NAME';
USER_TAB_PRIVS: Shows the privileges on tables and views for the current user. It’s a subset of ALL_TAB_PRIVS.
-- Query to find privileges on views for the current user SELECT * FROM USER_TAB_PRIVS WHERE TABLE_NAME = 'VIEW_NAME';
MySQL Data Dictionary Views:
INFORMATION_SCHEMA.TABLE_PRIVILEGES: Shows privileges for tables and views, including who has these privileges.
-- Query to find view privileges SELECT * FROM INFORMATION_SCHEMA.TABLE_PRIVILEGES WHERE TABLE_NAME = 'VIEW_NAME';
INFORMATION_SCHEMA.VIEW_TABLE_USAGE: Provides information about the tables used by views.
-- Query to find tables used by a specific view SELECT * FROM INFORMATION_SCHEMA.VIEW_TABLE_USAGE WHERE VIEW_NAME = 'VIEW_NAME';
SQL Server Data Dictionary Views:
sys.database_permissions: Provides details on database permissions, including those granted on views.
-- Query to find permissions on views SELECT * FROM sys.database_permissions WHERE major_id IN (SELECT object_id FROM sys.objects WHERE type = 'V');
sys.objects: Contains metadata about all database objects, including views.
-- Query to find views SELECT * FROM sys.objects WHERE type = 'V';
sys.database_principals: Contains information about database users and roles.
-- Query to find users and roles with privileges SELECT * FROM sys.database_principals;
Using Data Dictionary Views:
Querying for View Privileges:
You can use data dictionary views to determine which users or roles have access to a specific view and what type of privileges they have (e.g., SELECT, INSERT, UPDATE, DELETE).
Auditing and Security:
Reviewing privileges through data dictionary views is crucial for auditing purposes. It helps ensure that only authorized users have access to sensitive or critical views.
Managing Privileges:
By understanding the privileges granted on views, database administrators can make informed decisions about adjusting permissions or revoking access as needed.
Summary:
View Privileges: Refers to permissions related to accessing, creating, or modifying views.
Data Dictionary Views: Provide detailed information about who has what privileges on views within the database.
Examples: Different DBMSs have their own system catalog views for managing and querying view privileges (e.g., ALL_TAB_PRIVS in Oracle, INFORMATION_SCHEMA.TABLE_PRIVILEGES in MySQL, sys.database_permissions in SQL Server).
Usage: Useful for auditing, managing security, and ensuring proper access control.