The ? parameter markers

You can use the question mark symbol (?) to mark a parameter's place in an SQL statement or stored procedure.

Because the HCL® OneDB® .NET Core Provider does not have access to names for these parameters, you must pass them in the correct order. The order you add IfxParameter objects to an IfxParameterCollection object must directly correspond to the position of the placeholder ? symbol for that parameter. You use the ParameterCollection.Add method to add a parameter to a collection.