The databaseOwner is an optional parameter of the SqlDataProvider value.

In SQL Server 2000, the databaseOwner attribute was used to identify the user that “owns” the database objects.
In SQL Server 2005 and later it is the name of the Database Schema being used to create the database objects in.
By default it is set to “dbo” and in most cases this attribute should be left this way. However, some SQL Server DBAs (in particular in Shared Hosting Environments) may not grant the user you identify in the connection string db_owner privileges. In this case, set the databaseOwner attribute to your login user.
Note this user will need to have the following SQL Permissions, at a minimum:

• db_datareader (necessary for dotnetnuke)
• db_datawriter (necessary for dotnetnuke)
• db_ddladmin (neccessry for MemberRoles)
• db_securityadmin (necessary during installation of MemberRoles)