Cannot create master / detail / sub-detail relationship

Question

I cannot create a master / detail relationship - have read previous questions and answers on this but couldn't find an answer. The scenario is:

Project Payment (custom object) has a master / detail relationship to Contact (standard object) which has no master / detail relationships. Project Payment also has a master / detail relationship to Cost Centre (custom object) which has no master / detail relationships Created custom join object called Payment Allocation Payment Allocation has a master / detail relationship to Opportunity (standard object) which has no master / detail relationships. I now want to create a second master / detail relationship between Payment Allocation and Project Payment

Payment Allocation only currently has one master / detail relationship There are no master / detail / sub-detail relationships in place involving Project Payments I am able to create a lookup relationship between Payment Allocation and Project Payment.

Can anyone see why I can't create the Payment Allocation / Project Payment master / detail relationship, which will effectively become a master / detail / sub-detail relationship?

Answer 1

There can be two reasons why are you not able to create a matter detail.

1. You have already created two master detail relationship in the object. If you are due that there are only one md relationship, just check the deleted fields or simply look for the limits related list on the object.

2. You are trying to create a relationship which results in cyclic dependency i.e. the parent is dependent on child and child on parent and hence records can be created.

I believe one of them can be the reason.