Some important Order tables in Dynamics Ax 2012

CustGroup – The CustGroup table contains a list of groups into

which customers can be added. Every customer must

specify a CustGroup with which it is associated.

VendGroup – The VendGroup table contains definitions of vendor

groups.

CustTable - The CustTable table contains the list of customers

for accounts receivable and customer relationship

management.

VendTable –  The VendTable table contains vendors for accounts

payable.

SalesTable  - The SalesTable table contains all sales order headers,

regardless of whether they have been posted or not.

PurchTable –  The PurchTable table contains all purchase order

headers, regardless of whether they have been posted

or not.

SalesLine  - The SalesLine table contains all sales order lines,

regardless of whether they have been posted or not.

PurchLine –  The PurchLine table contains all purchase order lines,

regardless of whether they have been posted or not.

- Reference

http://www.winfosoft.com/blog/microsoft-dynamics-ax/microsoft-dynamics-ax-%E2%80%93-what-tables-compose-the-order-tables-in-dynamics-ax#sthash.QnSkRhYt.dpuf