Use o SMO para alterar os locais padrão do banco de dados do SQL Server

// Now create a database in the new location
Database smoDatabase = new Database(smoServer, database);

FileGroup fg = new FileGroup(smoDatabase, "PRIMARY");
DataFile df = new DataFile(fg, "File1", @"c:\sql\file1.mdf");
LogFile lf = new LogFile(smoDatabase, "Log01", @"c:\sql\Log1.ldf");


smoDatabase.Create();
smoServer.Refresh();