How to read sales order which has more than one document lines in SAP B1 by using DI API?.

Hi all,

I have a question about document lines in SAP B1.

I know how to read data into database by using DI API, but the problem is I do know how to read for example sales order which has more than one document lines.

$oOrder=$mycomp->GetBusinessObject(17);

$oOrder->CardCode="CM001";

$oOrder->DocDueDate="07/06/2016";

$oOrder->Lines->Itemcode="01-002";

$oOrder->Lines->Quantity=2;

So here I can replace CM001, 03/06/2016, 01-002 and 2 to variables like

$oOrder=$mycomp->GetBusinessObject(17);

$oOrder->CardCode=$CardCode;

$oOrder->DocDueDate=$DocDueDate;

$oOrder->Lines->Itemcode=$Itemcode;

$oOrder->Lines->Quantity=$Quantity;

How can I read sales order which has more than one document lines? I'm using php.

Please anyone can help me.