pls explain the entries in EDSDC and EDPAR table

Hi,

Iam working on Intercompany sales process through IDocs , and i have maintained entries in EDSDC and EDPAR table,

Like what i understood is in EDSDC table we maintain the relation between the customer, vendor , sales area and the order type....

If iam wrong can you pls explain me about the above two table functionality..

thanks in advance.

nawzir