Querying the System Tables

The system tables can be queried just as any other tables can. For example, this statement returns the names of all system tables in the database:

select name
from sysobjects
where type = 'S'

SQL Server has system stored procedures, many of which provide shortcuts for querying the system tables. For more information, see System Stored Procedures.

Caution System tables should not be directly altered by any user under any circumstance. For example, do not attempt to modify syslogs with a DELETE, UPDATE, or INSERT statement. Doing so makes it impossible for SQL Server to recover correctly in case of a system failure. In addition, attempting to delete all rows from syslogs will cause SQL Server to get into an infinite loop that eventually fill up the entire database.