Types of Associations

Hi Experts, Hope you are doing Good! Can you please advise how many types of associations can we have between Non persistable and persistable entities in Mendix?   Regards, Malay
1 answers


An association between a Non-persistable and persiatable must start in the NPE.

Mendix handles the associations as follows

  1. an object of the owning entity (the entity where the association starts with a dot) contains a member storing the ID of the referenced object(s)
  2. When storing in the database a join table will store the ID's of the  referenced records. So when you do have an association between a car and a model entity, ther will be a join table IDCar-IDModel. 

Knowing this, when you have an association between a NP and NPE it must start (dot) at the NPE otherwise the owning entity is the persitable entity. which would result in a join table which stores ID's of objects which will never enter the database. Hence a non-persitable entity cannot be persisted.


Long story short; only association that start in a NPE can be used. A 1-1 association results in ownership at both sides and cannot be used between a NPE and PE 

Hope it helps!!