更多关于symfony2的理论和关系

Question

So now I have set up my slideshow containers like: Geoarea, Building, Server

in different entities, mapped from one superclass.

Now the next problem I face is: I want to be able to relate these containers' contents to either one of the containers...

That was the reason I was initially just contemplating having one container entity and setting containertype with an INT flag, but OO-wise that isn't smooth or correct I think.

Now, I could of course have FK fields in my entity 'content' for each of the possible containers, and set them to nullable and only use one of them, but I feel like I am stuck in a rut here, think outside the box... I want to make fetching a container and it's related contents as simple as possible...

Each content is only related to ONE container, so having 3 FK-fields when never using more than one feels dumb...

Answer 1

You have two solutions. The first is to use Inheritance : Inheritance Mapping , but you will have some redundance in your database.

The second solution is to add a FK in your Child entity and not three in your Mother entity. Thereby, you will store common data in your Mother superclass.