Ignores Database set in connection string

[PhilMakower]

I am using this tool to try to migrate Contour 3 forms on Umbraco v7.15.10 to UmbracoForms v4.4.9 (to start with)
It takes no notice of the database set in the connection string I provide.
Adding code to log the DB_NAME() value shows that the main Umbraco database is being used!
So the table "UFForms" does not exist, for example.
I added code to pull out the "initial catalogue" from the connection string, and the call "USE " SQL.
Now DB_NAME() is as expected.

// https://stackoverflow.com/questions/10550541/how-to-get-database-name-from-connection-string-using-sqlconnectionstringbuilder
System.Data.SqlClient.SqlConnectionStringBuilder builder = new System.Data.SqlClient.SqlConnectionStringBuilder(connString);
string Database = builder.InitialCatalog;

string cmd = @"USE "+Database; // set current database
sql.ExecuteNonQuery(cmd);

/*string */cmd = @"SELECT DB_NAME()"; // name of current database
string db = sql.ExecuteScalar<string>(cmd);
LogHelper.Info<MigrationService>("ISqlHelper DB_NAME() returns =\"" + db + "\"");