symfony2 - ManyToMany with duplicate rows - php

Question

I currently have to Entities in my application:
Page
Block
A Page can have many Blocks, which are shared across many Pages, so it is quite obvious that the relation is a ManyToMany. However, I need to be able to add the same Block twice (or more) to the same Page. Doctrine creates the "page_block" join table automatically, but with page_id and block_id both as Primary Keys, therefore adding a duplicate throws an error.
Is it possible, without adding an additional Entity, to tell doctrine to allow duplicates on the Page--Block relation ?

Answer 1

Well, I'm not sure about that behavior in doctrine, but if that is the case, then you can do something that I almost always do. Represent the ManyToMany relation as two OneToMany-ManyToOne. You must create your own PageBlock entity and configure it's foreign keys.
class Page{
/**
* #var array
*
* #ORM\OneToMany(targetEntity="PageBlock", mappedBy="page", cascade={"all"})
*/
private $pageBlocks;
}
class Block{
/**
* #var array
*
* #ORM\OneToMany(targetEntity="PageBlock", mappedBy="block", cascade={"all"})
*/
private $pageBlocks;
}
class PageBlock{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var \stdClass
*
* #ORM\ManyToOne(targetEntity="Page", inversedBy="pageBlocks")
* #ORM\JoinColumn(name="id_page", referencedColumnName="id")
*/
private $page;
/**
* #var \stdClass
*
* #ORM\ManyToOne(targetEntity="Block", inversedBy="pageBlocks")
* #ORM\JoinColumn(name="id_block", referencedColumnName="id")
*/
private $block;
}
As you can see the primary key remains as ID, so problem resolved. I say almost always do because this is how I do it if I need an extra attribute in the relation(almost always it happens). I suspect that could be a way of do it with the ManyToMany annotation, but there is no difference with this approach.
Hope this help you.