How to get the Relationships data from Opportunity Transaction in CRM

Hi Friends,

Could you please let me know the table / class to fetch the relationships data associated with a single(main) opportunity.

There may be several object types like (activites, sub-opp's..etc) linked to a single main(source) opportunity.

I wanted the these fields information from Relationships tab From Opp transaction.

Source Item No.

Object Type

Target Trans/Object

Description

Type of Linkage

Could you please let me know.

Regards

Vijay