Each GP table has a series of associated stored procedures that allow records to be selected, inserted and deleted. These stored procedures have prefix 'zDP' followed by the table name. There are some stored procedures that contain business logic however for the most part, the GP business logic is performed in the dexterity code.
The architecture of eConnect differs in that all the business logic is contained inside of the stored procedures however these procedures are encrypted. If you looking for these eConnect stored procedures have the prefix 'ta'. Although I have directly called the eConnect stored procedures for a past project where I needed to wrap GP function calls into a larger database transaction, I would not recommend it. Better option is a use the .NET library or web service.
Regards
Andrew Dean