yup. thanks!

Oh I get it. But is this structure acceptable, thinking that if the transaction is purchase order, then POID will have a value but the TFID and RENTALID will be null?

Sample Table Structure:
...

But with this design, I would not be able to enforce referential integrity since there may be cases that the IDs will be of the same data but different transaction. What do you think?

I am currently working on this table. It will contain the transactions made. But the transaction varies, it may be a purchase order, transfer from inventory, rental, etc. I have different IDs for...