The information used by Microsoft® SQL Server™ and its components are stored in special tables known as system tables.
Note System tables should not be altered directly by any user. For example, do not attempt to modify system tables with DELETE, UPDATE, or INSERT statements, or user-defined triggers.
Applications should not be written to query the system tables directly. Applications should instead use any of these components to retrieve information stored in the system tables:
These components constitute a published API for obtaining system information from SQL Server. Microsoft maintains the compatibility of these components from release to release. The format of the system tables is dependent upon the internal architecture of SQL Server and may change from release to release. Therefore, applications that directly access the system tables may have to be changed before they can access a later version of SQL Server.
These tables store server-level system information.
These tables store database-level system information for each database.
These tables store information used by SQL Server Agent.
These tables store information used by database backup and restore operations.
| backupfile | backupset | restorefilegroup |
| backupmediafamily | restorefile | restorehistory |
| backupmediaset |
These tables are used by replication and stored in the master database.
| sysarticles | syspublications | sysservers |
| sysdatabases | sysreplicationalerts | syssubscriptions |
| sysobjects |
These tables are used by replication and stored in the distribution database.
These tables are used by replication and stored in the user’s database.