Link between Item and delivery

Hi ,

I want to know the link between item and deliveyr. Like for example, an sales order item ( no. 10) containing 10 quantities can be delviered 5 times( each containing 2 quantities) and line item ( no. 20) can contain one single delivery. I am working on a report where i have to link all the line item to its delivery number. I am trying to achieve this through GENIl but i am not able to indetify as to how to differentiate the different deliveyr numbers. In other words, can some one help me as to how to link the delivery number to its corresponding items?