dsn creation manually and programmatically

[pspsblog]

If I want to create a connection to database table, do I need to create DSN object manually in control panel and programmatically using connection string in create adodb connection object? Do I need to do both? Is there any advantage of doing both? or just either one method? which is suggested over another to query and for database check points. Can I do it programmatically successfully if I don't have admin access? If I want save the dsn object created programmatically in test data file, how to do that?