I have a lookup relationship and i am looking at ways to convert this relationship to Master Detail.

I have made sure that there are valid ids on the lookup and none of them are null. And when i try to change field type there is only option of Lookup to select. What is the process to change the lookup to master detailenter image description here


  • is the master detail relation limit on that object is full already?
    – Anurag
    Commented Aug 10, 2016 at 16:25
  • is there a way i can check that easily ?
    – Prady
    Commented Aug 10, 2016 at 16:27
  • You can check on Object definition. You can add max 2 master detail relationships on a object
    – Devendra
    Commented Aug 10, 2016 at 16:29
  • Wanted a master detail on contract object for opportunity. i dont have any master detail on contract object
    – Prady
    Commented Aug 10, 2016 at 16:35

1 Answer 1


Some objects, like User, can't have master-detail relationships associated to them, and many standard objects cannot have a custom master-detail relationship to another object. You'll also be prohibited from making master-detail relationships if you've already reached your maximum. If you're looking for the behavior of master-detail relationships on this object, you'll most likely need to implement the sharing, cascade deletes, and/or roll-up summary fields via triggers, flows, etc.

  • Its on contract object. i guess the restriction could also be on this object as well
    – Prady
    Commented Aug 10, 2016 at 16:34
  • @Prady Yes, Contract can't have custom master-detail relationships.
    – sfdcfox
    Commented Aug 10, 2016 at 16:42

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