Relationship to same entity MER

1

I am developing my tcc and I came across the following doubt in my MER (Model entity relationship).

I have a client entity that pays another client, but just how do I represent it in ER?

Type so I'm talking about:

CLIENTE (nenhum,muitos)  ---- PAGA ---- (nenhum,muitos) CLIENTE

Would it look that way?

    
asked by anonymous 29.06.2016 / 14:36

1 answer

1

The book claims to be a recursive relationship.

I think it's possible to make a comparison with the example

I made a drawing on draw.io to represent the answer.

InthiswayitispossibletorepresentthatthereareNclientsthatreceiveremunerationfromotherclients,andthatthereisatleastoneclientthatassumesthepositionofremunerator.

Notethatthenumber"1" on the payer's side indicates that in a transaction there can only be one person who is paying the other, that is, not for 2 or more people to make a payment for the same person in the form of a single record (this does not make sense)

If a (paid) person is receiving an amount of more than one (remunerative) person, then there must be 2 separate payment records.

The answer came from the book: Database Systems 5th Edition Authors: Elmasri, Ramez Navathe, Shamkant B. Year: 2011

    
30.10.2017 / 03:14