doctrine：migrations：diff为ManyToMany关系生成2个表而不是一个表

Question

I have two entities: product and tag connected by many-to-many relation.

Here is a part of Product entity:

/**
 * @ORM\ManyToMany(targetEntity="Tag", inversedBy="products")
 * @ORM\JoinTable(name="product_tag")
 *
 * @var \Doctrine\Common\Collections\ArrayCollection
 */
private $tags;

and the similar at Tag:

/**
 * @ORM\ManyToMany(targetEntity="Product", inversedBy="tags")
 *
 * @var ArrayCollection
 */
 private $products;

The issue is when I generate migration using php app/console doctrine:migrations:diff I get both product_tag and tag_product generated. While I expect to get only the first one.

What have I done wrong?

Answer 1

Taken from the Doctrine documentation (Association Mapping > Owning Side and Inverse Side):

The inverse side of a bidirectional relationship must refer to its owning side by use of the mappedBy attribute of the [...] ManyToMany mapping declaration. The mappedBy attribute designates the field in the entity that is the owner of the relationship.

The owning side of a bidirectional relationship must refer to its inverse side by use of the inversedBy attribute of the [...] ManyToMany mapping declaration. The inversedBy attribute designates the field in the entity that is the inverse side of the relationship.

Basically you cannot use inversedBy in both entities. You should use it on the owning side. mappedBy should be used on the other side.

Read: Picking Owning and Inverse Side