Can I set up a Symfony2 ORM inheritance relationship using MySQL? - mysql

Question

I have one table tech_note and I would like to have 3 tables more tech_note_es, tech_note_en and tech_note_fr (in a future many more tables). And the tech_note can be in the 3 tables at same time.
My idea is attach to tech_note_en and automatically receive attributes from tech_note.
SECOND EDIT:
I would like somthing like that: I search in Tech_note_EN by ID=3 (I recive fields from tech_note_EN with ID=3 and fields tech_note with ID=3.
But if I search in Tech_note_ES BY ID=3 (I recive fields from tech_note_ES with ID=3 and tech_note fields from tech_note with ID=3 (the same fields from above)
The tech_note have a ID=3. Tech_note_EN have ID=3, and Tech_note_ES have ID=3
EDIT WITH NEW CLASSES:
Now I have this error:
Entity 'EVTS\FrontendBundle\Entity\Tech_note_en' has a composite identifier but uses an ID generator other than manually assigning (Identity, Sequence). This is not supported.
TECH_NOTE
abstract class Tech_note {
/**
* #var integer $id
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var datetime $control_date
*
* #ORM\Column(name="control_date", type="datetime")
*/
private $control_date;
/**
* #var string $comment
*
* #ORM\Column(name="comment", type="string")
*/
private $comment;
TECH_NOTE_EN
class Tech_note_en extends Tech_note {
/**
* #var integer $tech_note_id
*
* #ORM\Id
* #ORM\Column(name="tech_note_id", type="integer")
* #ORM\OneToOne(targetEntity="tech_note")
* #ORM\JoinColumn(name="tech_note_id",referencedColumnName="id")
*/
private $tech_note_id;
/**
* #var text $symptom
*
* #ORM\Column(name="symptom", type="text")
*/
private $symptom;
/**
* #var text $cause
*
* #ORM\Column(name="cause", type="text")
*/
private $cause;
/**
* #var string $solution
*
* #ORM\Column(name="solution", type="string")
*/
private $solution;
OLD CLASSES
TECH_NOTE
class Tech_note {
/**
* #var integer $id
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var datetime $control_date
*
* #ORM\Column(name="control_date", type="datetime")
*/
private $control_date;
/**
* #var string $comment
*
* #ORM\Column(name="comment", type="string")
*/
private $comment;
TECH_NOTE_EN
class Tech_note_en
{
/**
* #var integer $tech_note_id
*
* #ORM\Id
* #ORM\Column(name="tech_note_id", type="integer")
* #ORM\OneToOne(targetEntity="tech_note")
* #ORM\JoinColumn(name="tech_note_id",referencedColumnName="id")
*/
private $tech_note_id;
/**
* #var text $symptom
*
* #ORM\Column(name="symptom", type="text")
*/
private $symptom;
/**
* #var text $cause
*
* #ORM\Column(name="cause", type="text")
*/
private $cause;
/**
* #var string $solution
*
* #ORM\Column(name="solution", type="string")
*/
private $solution;

Answer 1

There is an awesome solution to your problem, which is single table inheritance
What this does is basically Have one central table with general fields, and links to other table with specific fields.
In your case I would use this architectural model:
abstract class TechNote (abstract common entity, which contains common fields)
class TechNoteEn extends TechNote (specific entity which inherits common fields and adds specific EN fields)
and so on.
I find this as the best architectural solution for your problem.

Answer 2

That's your ORM's job.
// Assuming $tech_note_en is a Tech_note_en instance
$tech_note_en->getTechNote();
(something like this ^^)