删除与学说的关联

Question

I'm using Doctrine and have three tables. artists , categories , artist_category . I have an import script which imports artists, categories and the associations from a site and saves it into the database. The problem I'm having is removing an association. Let's just imagine I have one artist and this artist is associated with three categories. Now in the next import one artist_category association got removed. What I want to do now is to remove the categories from the association table that aren't relevant anymore.

Let's say my artist has the ID 254 and the category that should be removed has the ID 4.

My database table currently looks like this

Now I have an array with all categories that the artist should be associated with

array(1) {
  [0]=>
  string(1) "3"
}

This would mean, that in my next step I have to remove the association artist_id (254) and artistcategory_id (4).

What I'm doing is this

foreach ($artist->getArtistCategories() as $artistCategory) {
    if (!in_array($artistCategory->getId(), $artistCategories)) {
        $artist->removeArtistCategories($artistCategory->getId());
    }
}

which is working. In the case of category 4 the method removeArtistCategories is called. However, the deletion doesn't work. This is what I tried

$this->artistCategories->removeElement($artistCategory);

returns false

$this->artistCategories->remove($artistCategory);

returns null

$this->artistCategories->contains($artistCategory)

returns false

However, when I var_dump($this->artistCategories) I'm getting pretty much information about the categories. Deletion however, doesn't work. What am I doing wrong?

Answer 1

Doctrine works with entity objects, not with IDs. So instead:

$artist->removeArtistCategory($artistCategory->getId());

try

$artist->removeArtistCategory($artistCategory);

and define your remover like described in the Doctrine documentation:

http://doctrine-orm.readthedocs.org/projects/doctrine-orm/en/latest/reference/working-with-associations.html#association-management-methods

public function removeArtistCategory(Category $category) {
    $this->artistCategories->removeElement($category);
}

Note that I renamed the method removeArtistCategories to removeArtistCategory as you just remove one entry and not multiple categories. This is important because removers and adders have a naming convention just like getters and setters and you will have problems using some components for doctrine if you don't define your methods correctly.

I just assumed you have a toMany relationship between Artist and Category because I don't know your entity definition, I'd need more information to give you a proper solution. So this code is untested and might not work!