Symfony2-处理对象的正确方法

Question

I have things working perfectly, but I am wondering if I should do it differently after reading this

Essentially, I have a Entity class called AvailabilityAlert. At the moment, this is pretty much a static Entity, the only fields it has in it relate to itself.

I then have a Entity class called FlightNumbers, and in it I have

/**
 * @ORM\ManyToOne(targetEntity="Nick\AlertBundle\Entity\AvailabilityAlert", inversedBy="flightNumbers")
 * @ORM\JoinColumn(name="availability_alert_id", referencedColumnName="id")
 */
private $availabilityAlert;

So $availabilityAlert is a link to the id field in the AvailabilityAlert Entity class.

So this all works great, an AvailabilityAlert has one or more FlightNumbers. According to that article, I should show this in my AvailabilityAlert class. So should this class have

/**
 * @ORM\OneToMany(targetEntity="Nick\AlertBundle\Entity\FlightNumbers", mappedBy="availabilityAlert")
 */
protected $flightNumbers;

And then a __construct which adds it to an ArrayCollection? If so, what is the advantage of doing this?

As I say, everything works perfectly the way I currently have it. However, I want to learn the correct way of doing things.

Answer 1

Adding an ArrayCollection on __construct allows you to use methods of Collection interface like add, remove, contains, ...

This can come handy when using a newly created entity, eg

(new FlightNumbers)->getAvailabilityAlert()->add(new AvailabilityAlert);