Stonefield Query normally uses a connection string to connect to an ODBC data source, even if you specify a data source name (DSN) in the Add Database dialog. Using a connection string has the advantage that the DSN doesn't have to exist on the user's system. Also, connection information can easily be changed dynamically in a GetDataSources script for a database.
However, there are a couple of instances where using a connection string rather than a DSN isn't a good idea:
If your Stonefield Query project is used with a commercial application that uses DSNs, you'll likely set the User Can Manage Data Sources setting to True. Doing so changes the Use DSNless Connection setting to False automatically and you cannot edit its value.
Some database engines, such as Btrieve, Pervasive (the new name for Btrieve), and Adaptive Server Anywhere, do not support connection strings. In that case, a DSN must be specified instead.
Set the Use DSNless Connection property to False if you want to use a DSN rather than a connection string.