To connect to Square, you can use either a DSN or an ODBC connection string. Both of these methods use the sql package's Open function.

Connect to a DSN

To connect using a DSN:

db, _ := sql.Open("odbc", "DSN=CData Square Sys;")
defer db.Close()

Provide a Driver Connection String

To connect using an ODBC connection string:

db, _ := sql.Open("odbc", "DRIVER={CData ODBC Driver for Square};OAuthClientId=MyApplicationId;OAuthClientSecret=MyApplicationSecret;CallbackURL=http://localhost:33333;LocationId=MyDefaultLocation;")
defer db.Close()