CODEWITHSUNDEEP
phpzend-frameworkannotationsdoctrine-ormone-to-many
Mr B
Mr B

Reputation: 4130

How to use many to one associations in Doctrine 2

I'm using Doctrine 2 in Zend.

I'm trying to figure out how to access the properties/method for related models from the current object.

For example, we have two tables: Schools and Students.

Many Students belong to a school, so this is a many to one relationship and I'm only interested in listing all the students for each school. I do not wish to query student records to find the details of the school they belong to therefore this is classed as a unidirectional relationship.

Now to set up the many to one relationship in Doctrine 2 between the tables I'd add this in the Students entity, as it is the owning side:

/**
 * @ManyToOne(targetEntity="Schools")
 * @JoinColumn(name="school_id", referencedColumnName="school_id")
 */
private $schoolId;

Where the name values correspond the column names in the students table and schools table respectively.

So if I have an object of a Schools record, how do I access the student properties/methods? 

echo $oSchool->Students->getName(); // doesn't work

I can't understand what I have done wrong, the proxy class is being generated. Appreciate it if anyone could point me in the right direction.

Upvotes: 3

Views: 7555

Answers (3)

khanz
khanz

Reputation: 203

For those who are facing this issue: "Fatal error: Call to a member function setValue() on a non-object in C:\xampplite\htdocs\test\library\Doctrine\ORM\PersistentCollection.php on line 168 –"

Solution: Need to replace mappedBy value with doctrine property value instead of Table column name

Ex:

Correct Syntax: @ORM\OneToMany(targetEntity="Test\Entity\School", mappedBy="school")

Wrong Syntax: Correct syntax: @ORM\OneToMany(targetEntity="Test\Entity\School", mappedBy="school_id")

Upvotes: 1

MrMorice
MrMorice

Reputation: 129

In the Schools entity you'd want to have something like this

/**
 * @param \Doctrine\Common\Collections\Collection $property
 * @OneToMany(targetEntity="Students", mappedBy="school")
 */
private $student;

public function __construct() {
    $this->student = new \Doctrine\Common\Collections\ArrayCollection();
}

public function getStudent() {
    return $this->student;
}

With this you could do something like the following, which gives you an ArrayCollection with all student objects 

$studentsArray = $school->getStudent();

Hope that helps... Docrine 2 is very powerful but some things are not documented very well. Some more information on this in the Documentation at Working with Assiciations.

Upvotes: 6

Mr B
Mr B

Reputation: 4130

I've made some progress. I read the 'Working with Objects' section of Doctrine 2's documentation.

Associated objects can be accessed by something like this (according to the example given in my question):

$oStudent->getSchoolId()->getName(); // gets a student's school's name by traversing the school class

However in my orignal question, I wanted to access the students belonging to a school via the schools object. I am completely stumped on how to do this, It seems to me its not possible.

Upvotes: 0

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