Associations - Parent/Child Relationship

In several of the learning modules, we are supposed to create a 1-* relationship with other objects, and it specifies which object is to the be the parent and which is the child. However, the Modeler does not allow the option of 1 parent per many children. The only way to get a 1-* relationship is to make the “many” entity the parent. Am I missing something? What implications does the parent/child definition have?
4 answers

In addition:
If you really need the owner entity to have a list of associated objects, you can achieve this by having a *-* association with your entity as owner.


How are you setting which object is the owner? With 1-* relationships, the owner should generally just be set to “default”, that should keep things working as intended.

As for the meaning of a parent-child relationship, Sebastiaan van den Broek covers it quite well in the answer here:

“It is (or can be at least), the side where you start drawing from and where the association is stored is the parent, but this parent is the * side which points at the 1 side. This makes it so the association field only has to contain 1 identifier in most cases, which is quite useful in foreign-key constructions (even though it doesn't work like that in the database currently).

It doesn't necessarily say anything about the logical relationship between the entities, especially not in this case where a (logical) parent can have multiple (logical) children.”


Here’s what the tutorial says: 

ProgramItem should have 1-* reference on Artist. 

Name: ProgramItem_Artist

Type: Reference

Owner: Default

Parent: ProgramItem

Child: Artist

I have the settings exactly as indicated, but there is no option for multiple artists associated with one program item. Only one artist associated with one program, one artist with multiple programs, or multiple artists with multiple programs.



As many features in Mendix are quite intuitive this can create some confusion indeed, thanks Tim.