Passing the Key in $expand Option
Here is my ODATA Service link.
By Passing the Work Order type as '36'. I will get the Order details ( ZORDDATA Custom Table ) and Order Part Details ( ZORDPART table)
For a Single Order . there will be multiple parts. So I use the $Expand to get the Order part details ( Work type will be the Key)
Now If I the User does not pass the Work type (or value as '' or blank) , I wont get any Part details though I will get other order details from ZORDDATA table.
Now the Requirement : I need to Fetch the Order type from ZORDDATA and Pass it to ZORDPART and get part details without directly passing the Work type field in the ODATA Service,
Can you provide details about your Entity Properties and the association between the entities.
Also i feel your scenario is more around the passing data and not technical issue, am I right or missing something?