Installation and Upgrade > Installation and Configuration Guide > Database Installation > Installing SQL Server > Installation Steps
  
Installation Steps
Configure User Accounts for SQL Server and Windchill Services
The SQL Server instance will be configured to use Mixed Mode authentication when installing in order to support Windchill. With Mixed Mode authentication, SQL Server provides a built-in SQL Server Authentication account with the username sa. This account is utilized only during the installation of the Windchill database and tables.
The Windchill installer uses the sa account to install the database and tables only. It is not used to access Windchill data from the application server post configuration. Best practice in general is for the sa account to have a strong password and to disable its access to the Windchill data when not installing.
During the database installation process, the PSI installer requires that you specify another new user name and password for database access. This user name provided will generate a database of the same name along with a local user within SQL Server.
* 
You cannot use a domain user to access SQL Server from Windchill or during installation. Do not grant permissions to domain groups to access the database since this will create a potential security vulnerability. Grant permission only to specific domain users.