Question

Using Symfony2 and orm.yml files to map the entities into the database how can I create a 3-ary relationship between entities A,B,C that result in a D table that contain A_PrimaryKey, B_PrimaryKey, C_PrimaryKey the relation between the entities are this:

A-B manytomany
A-C manytomany
B-C manytomany

Answer 1

So, your basic model would look like this:

A 1:n D
B 1:n D
C 1:n D

The yml for A would look like this:

Acme\TestBundle\Entity\A:
    type: entity
    # ...
    oneToMany:
        products:
            targetEntity: D
            mappedBy: d

You can just repeat this with B and C. For D, it would look something like this:

Acme\TestBundle\Entity\D:
    type: entity
    # ...
    manyToOne:
        a:
            targetEntity: A
            inversedBy: as
            joinColumn:
                name: a_id
                referencedColumnName: id
        b:
            targetEntity: B
            inversedBy: bs
            joinColumn:
                name: b_id
                referencedColumnName: id
        c:
            targetEntity: C
            inversedBy: cs
            joinColumn:
                name: c_id
                referencedColumnName: id

Give it a try. Maybe try to map A and D first. If this works, continue with B. So you are more likely to catch errors on the way!