Doctrine 2 one-to-one via composite key of both entities - symfony

Question

I have a question similar to this one.
I need a relation one-to-one through composite key, is it possible? I've read about this but it's referred to one-to-many relation
class Header{
/**
*
* #ORM\Id
* #ORM\Column(name="UH1", type="integer", nullable=false)
*/
protected $key1;
/**
*
* #ORM\Id
* #ORM\Column(name="UH2", type="integer", nullable=false)
*/
protected $key2;
/**
* #ORM\OneToOne(targetEntity="Detail", mappedBy="header")
*/
protected $detail;
}
class Detail{
/**
*
* #ORM\Id
* #ORM\Column(name="UD1", type="integer", nullable=false)
*/
protected $key1;
/**
*
* #ORM\Id
* #ORM\Column(name="UD2", type="integer", nullable=false)
*/
protected $key2;
/**
* #ORM\OneToOne(targetEntity="Header", inversedBy="detail")
*/
protected $header;
}
I mean there are two columns as Id per entity... do i need to add the joincolumn ?

Answer 1

You need to use the JoinColumns annotation that allows to define an array of JoinColumn annotations to handle such cases for ManyToOne or OneToOne associations.
With the following entities:
AppBundle\Entity\A.php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity()
*/
class A
{
/**
* #ORM\Id
* #ORM\Column(name="key1", type="integer", nullable=false)
*/
private $key1;
/**
* #ORM\Id
* #ORM\Column(name="key2", type="integer", nullable=false)
*/
private $key2;
/**
* #ORM\OneToOne(targetEntity="AppBundle\Entity\B", mappedBy="a")
* #ORM\JoinColumns(
* #ORM\JoinColumn(name="key1", referencedColumnName="key1"),
* #ORM\JoinColumn(name="key2", referencedColumnName="key2"),
* )
*/
private $b;
}
AppBundle\Entity\B.php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity()
*/
class B
{
/**
* #ORM\Id
* #ORM\Column(name="key1", type="integer", nullable=false)
*/
private $key1;
/**
* #ORM\Id
* #ORM\Column(name="key2", type="integer", nullable=false)
*/
private $key2;
/**
* #ORM\OneToOne(targetEntity="AppBundle\Entity\A", inversedBy="b")
* #ORM\JoinColumns(
* #ORM\JoinColumn(name="key1", referencedColumnName="key1"),
* #ORM\JoinColumn(name="key2", referencedColumnName="key2"),
* )
*/
private $a;
}
I could achieve the desired behaviour. When asked for a schema update, Doctrine outputs:
CREATE TABLE a (key1 INT NOT NULL, key2 INT NOT NULL, UNIQUE INDEX b_uniq (key1, key2), PRIMARY KEY(key1, key2)) DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci ENGINE = InnoDB;
CREATE TABLE b (key1 INT NOT NULL, key2 INT NOT NULL, UNIQUE INDEX a_uniq (key1, key2), PRIMARY KEY(key1, key2)) DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci ENGINE = InnoDB;
ALTER TABLE a ADD CONSTRAINT FK_E8B7BE432C5C6450B55535EA FOREIGN KEY (key1, key2) REFERENCES b (key1, key2);
ALTER TABLE b ADD CONSTRAINT FK_71BEEFF92C5C6450B55535EA FOREIGN KEY (key1, key2) REFERENCES a (key1, key2);