The System Administrator login ID for administering a computer running Microsoft SQL Server version 6 and configured for standard security. The SA account is the main administrator for the SQL Server environment and can be used to:
The SA account can access any application or database on the SQL Server system. If the server running SQL Server is configured for standard security, a password should be assigned to the SA by using the SQL Server Enterprise Manager. There are no restrictions on what the SA can do in SQL Server.
Anyone who has SA access to a server running SQL Server can also use the xp_cmdshell command to run almost any Microsoft Windows NT or Windows 2000 shell commands and change the configuration of your Windows-based server. So be careful who you grant SA access to.
In SQL Server 7, user accounts that are members of the Sysadmin fixed server role have the rights and privileges of the SA account. The SA account is provided in SQL Server 7 only for backward compatibility with earlier versions of SQL Server. Although SA can be used as a kind of back door to the system if you’re having problems with other administrator accounts, it should not be used for general-purpose administration of the server running SQL Server.