When you create a database, you will be asked for the Database Account. The Database Account is a login of the SQL Server that all users and services will use to access the database. We recommend that you create a dedicated SQL Server login for this task.
For SQL Server Authentication
SQL Server logins can contain from 1 to 128 characters, including only letters and numbers. Logins cannot contain symbols, such as a semicolon (;) or a backslash (\); be a reserved login name, for example
public, or already exist; or be NULL or an empty string ('').
Permissions and Roles
The Database Account does not require any server-level roles. As soon as you specify the Database Account during the database creation, the Database Management tool grants these permissions to this SQL Server login:
db_owner fixed-database role for the database.
VIEW ANY DEFINITION and VIEW SERVER STATE SQL Server permissions.
db_datareader and db_datawriter fixed-database roles to all archive databases found on this SQL Server instance.
About Making Changes
Any changes made to this SQL Server login on the SQL Server will require the Alloy
Please consider to never change the Database Account, or do it only when it is absolutely necessary.