教义类表继承-多种类型

Question

I'm trying to make a Listing system for a classifieds-like site in Symfony. I want to have multiple Listing types with different fields (and some common fields).

I was going to make a main Listing class which would have all of the common fields (name, description, price) and then subclasses with the fields specific to the different types.

Through my research, it sounds like Class Table Inheritance in Doctrine is the best solution. Am I correct in this? I may have up to 10 "subtypes" and heard it may not be great for performance.

    /**
    * Listing
    *
    * @ORM\Table(name="listing")
    * @ORM\InheritanceType("JOINED")
    * @ORM\DiscriminatorColumn(name="discr", type="string")
    * @ORM\DiscriminatorMap({"listing" = "Listing","recreation-vehicle" = "RecreationVehicle","vehicle" = "Vehicle","event" = "Event","classified" = "Classified","buyandsell" = "BuySell","real-estate" = "RealEstate","business" = "Business"})
    */
    class Listing
    {

}

Thanks!

Answer 1

In the doctrine documentation of Class Table Inheritance you can find some considerations using it. Some important facts excerpted:

• provides the greatest flexibility at design time, since changes to any type are always limited to that type's dedicated table
• This strategy inherently requires multiple JOIN operations to perform just about any query which can have a negative impact on performance, especially with large tables and/or large hierarchies

As you have only one inheritance level (all listings extends your base Listing ) it should not a big impact.