Open Jpa OneToMany parent relationship with two level down child

Question

How can I make a relationship with a second-level child using openjpa.

Parent -> Child -> GrandChild

Parent has a property lets say, plant, the child does not have it, however the grand child do. So, how can I make a relationship to the grand child directly from parent in order to get only those children having same plant as their parent in their child level(GrandChild). (Preferably one sided).

Answer 1

The simplest option is to move from Parent --> Plant --> GrandChilds.

Meaning you will need:

• A ManyToOne in the Parent with Plant
• A OneToMany in the Plant with List< GrandChild >

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Additionally (to be coherent)

• A OneToMany in the Plant with List< Parent >
• A ManyToOne in the GrandChild with Plan

After doing so you will be able to do:

parent.getPlant().getGrandChilds()