PR number present at Transaction level.But not in the DB table(EKPO)

Hi Experts.

In transaction ME23N (Display Purchase Order) for an Purchase order, I'm able to see the Purchase requsition(BANFN) number displayed at each line item.

When i checked the corresponding table EKPO (Purchasing Document Item) table. I found that EKPO-BANFN is blank.

I wonder data is present at transaction level but not at the database table level.

Can please help in solving this issue?

Thanks in advance!!!

Regards

Balaji R