Associations between Persistable and Non Persistable entity

How many associations are there between persistable and non persistable entity in Mendix?
4 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 




Are you Start your association from non persistable entity ?





I tried to give 1-1 association between persistable and non persistable entity but it throws error

as below . When to resolve error I tried to make owner as Default then the association changes to 1 – * automatically.


HI Satyam,
There are 3 types of association in Mendix 1 – 1, 1 – *, and * – *. You can use all three between Non-persistable and persistable Entities.  But you have to make sure all the association should start from Non-Persistable to Persistable.


This will be different when the Same Entities are used for the Native application and the error will appear in the errors pane of your Studio pro.