The SQL Server account provides the SMS services with access to the SMS site database and the software metering database. Each primary site requires a SQL Server account. The account used depends on the type of SQL Server security you specified during SQL Server Setup. During SQL Server Setup, you specified either standard security or integrated security. If you specified standard security, you entered a user account (by default, sa) and password to use to connect to a SQL Server database. If you specified integrated security, SMS uses the account you logged on with to access SQL Server.
You specify the SQL Server account during SMS Setup. You can change the user account for the SQL Server account in the Accounts tab of the Site Properties dialog box.
Specify a New SQL Server Account
SMS Accounts Configuration Overview