To implement your requirement you would need a data provider. List & Label provides these data providers in the programming languages C++, Delphi or in .Net languages. I’d like to guide you to the corresponding sections within our programmer’s manual, for example here, here and here.
We also recommend to have a look at the source code samples that are provided with List & Label for various programming languages to get started quickly. You will find them in the “Samples” subfolder in the List & Label start menu.