How to check whether a link is created between two requirements?

Hello,

I want to check whether a link is created between two requirements or not, linking is within or outside of module? My scenarios are:

First I create a link between two requirements it could be In-link, Out-link within or outside of module for this I have source_id and target_Id of requirements also I do have source_module & target_module name.

Then I have to check whether link exist between the above mentioned Id's of respected modules or not?

How can i achieve it using DXL?