From my experience with EDI for year with Health Care and Accounting data, you really do not combine your database with EDI. EDI is a set of standards designed to be independent of communication and software technologies. Is purpose is to allow any two software packages to be able to pass data.

So to use EDI:

1) Data is exported from a database and reformatted into a standard format (EDI standard) the everyone agrees to follow.

2) the file is transmitted

3) The recipient reads the standard EDI format and translate the data so that It can be imported their database format.