Doctrine: Many-to-Many without Join Table on Legacy Database

Question

My question is essentially this one , only I am using Doctrine 2 instead of Hibernate. I'm given this (simplified) DB structure:

PRODUCT                      TABLE_ENTRY
-------                      -----------
ID int primary key           ID int primary key
NAME varchar                 IDX int
GROUPING_CODE varchar(32)    GROUPING_CODE varchar(32)

• GROUPING_CODE is not unique in both tables
• Each TABLE_ENTRY is associated with n PRODUCTs

I would like to map this relation in one direction, as described in the answer to said Hibernate question:

/**
 * @ORM\OneToMany(targetEntity="Product")
 * @ORM\JoinColumn(name="grouping_code", referencedColumnName="grouping_code")
 */
private $products;

In Doctrine this does not seem to work, because the " mappedBy " attribute is required by OneToMany . Is there an other way to achieve a similar mapping in Doctrine? Read-only would be sufficient, too.

Answer 1

In the meantime I found a solution that seems to be working and might be sufficient in my case:

/**
 * @ORM\ManyToMany(targetEntity="Product")
 * @ORM\JoinTable(name="product",
 *        joinColumns={
 *            @ORM\JoinColumn(name="grouping_code", referencedColumnName="grouping_code")},
 *        inverseJoinColumns={
 *            @ORM\JoinColumn(name="id", referencedColumnName="id")}
 *      )
 */
private $products;

Essentially, this is using the target table PRODUCT itself (again) as the join table.

This does feel like a hack and probably is, but it seems to be doing what is required. I am sure it would fail utterly when used to write to the database, though.

Update: One huge draw-back of this solution is that DB schema update, creation, and dump won't work because Doctrine complains that the table PRODUCT already exists.