Object relations

Object relations in a meta field

The relationships between WordPress objects are treated with a normal meta field.

After selecting the relationship field type this box will appear:

From, to, relation

From the left to the right you have:

  • From - The first entity involved in the relation

  • To - The second entity involved in the relation

  • Relation - The relationship between the selected entities

If you select a Bidirectional reaction (see below) a new box called Inversed field on target post will be displayed.

Choose the corresponding field type.

Automatically this field type will be set as a relationship one (inversed of the selected one).

Relationships types

  • One-to-One - Unidirectional - The current object can be related to one object

  • One-to-One - Bidirectional - The current object can be related to one object and there is an inversed field on the target object

  • One-to-many - Unidirectional - The current object can be related to many objects

  • One-to-many - Bidirectional - The current object can be related to many objects and there is an inversed field on the target object

  • Many-to-one - Unidirectional - Many objects belonging to the current object can be related to one object

  • Many-to-one - Bidirectional - Many objects belonging to the current object can be related to one object and there is an inversed field on the target object

  • Many-to-many - Unidirectional - Many objects belonging to the current object are related to many objects

  • Many-to-many - Bidirectional - Many objects belonging to the current object can be related to many objects and there is an inversed field on the target object

Example

Suppose you have two custom post types: one called Florist and one called Flower.

The Florist may have many flowers, and any flower belongs to only one Florist.

Create a field called flowers on the Florist and a field called florist on the Flower (create them as simple text).

Then, go to Florist and transform the flowers fields in a One-to-many bidirectional relation:

  • Select Flower as From entity

  • Select Florist as To entity

  • Select One-to-many bidirectional as the relation

  • Select florist as field target

You are done! automatically on the Flower side, the florist field is now a Many-to-one bidirectional relation.

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