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symfonydoctrinecommentsblogsrelation
khalid sookia
khalid sookia

Reputation: 313

Symfony2 which doctrine relationship for blog between posts and comments

I am building a blog with symfony2 and I am wondering which doctrine relation mapping should be used for the comments. The thing is that I would like to use the comments in different parts, like commenting on pictures (which are not posts) or commenting on comments. So I need my comment entity to be independent of the post.

I wanted to try the OneToMany unidirectionnal but it forces a unique key on the post which is not great.

Thanks for your help

Upvotes: 1

Views: 220

Answers (2)

Alex Rock
Alex Rock

Reputation: 830

Simple way

The simplest way would be to create a OneToMany relationship for each linked entity. It's quite ugly and maybe is not effective when searching entities, but it works.

The mapping would be similar to this:

class Comment
{
    /**
     * @ORM\ManyToOne(targetEntity="Post")
     * @ORM\JoinColumn(nullable=true)
     **/
    protected $post;

    /**
     * @ORM\ManyToOne(targetEntity="Picture")
     * @ORM\JoinColumn(nullable=true)
     **/
    protected $picture;

    /**
     * @ORM\ManyToOne(targetEntity="Comment")
     * @ORM\JoinColumn(nullable=true)
     **/
    protected $comment;
}

You'll have to handle security by yourself to make sure the comment has at least ONE linked element, and searching might be harder, but it's a basic way to do it.

Complex way

The most effective way to do it (but maybe the most complex) would be to create a "discriminant" property and a "element-to-be-commented" property, coupled with a Custom Doctrine hydrator to retrieve all objects at once, but each one being the correct entity.

The "element-to-be-commented" property would then be either a Comment, Picture or Post, and the discriminant would be here to tell which class is linked.

In SQL terms, it means no foreign key between tables, and that the element_id is dependent of the discriminant.

Upvotes: 2

Francesco Abeni
Francesco Abeni

Reputation: 4265

You may want to take a look at Single Table Inheritance. Disclaimer: I don't have direct experience with it, but it's been suggested often as an answer to similar questions.

Upvotes: 0

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