To connect to Square, you can use either a DSN or an ODBC connection string. Both of these methods use the odbc_connect function.

Connect to a DSN

To connect using a DSN:

$cnx = odbc_connect("CData Square Sys", "", "");

Provide a Driver Connection String

To connect using an ODBC connection string:

$cnx = odbc_connect("DRIVER={CData ODBC Driver for Square};OAuthClientId=MyApplicationId;OAuthClientSecret=MyApplicationSecret;CallbackURL=http://localhost:33333;LocationId=MyDefaultLocation", "", "");