Creating an object without knowing the class name

[NotionCommotion]

I have classes "dogs", "cats", and "mice", and each extends class "animals".

 

I have a table with primary integer key "id" (1, 2, 3) and unique column "animal_type" ("dogs", "cats", and "mice").

 

Given id of 2, how can I create a cats object without first querying the database to get the animal type?

[Jacques1]

PHP isn't clairvoyant.

[NotionCommotion]

PHP isn't clairvoyant.

 

Didn't know if I could/should create an object $animal=new animal(2) use the constructor to query the DB and return the object based on the appropriate class.  Sounds a little recursive, so I expect not, but thought there might be something similar which was acceptable.

Edited August 20, 2016 by NotionCommotion

[Jacques1]

A constructor cannot return an arbitrary object. A new animal is in fact a new animal, not a new dog or cat.

 

Mapping rows of the same table to different classes sounds like a strange idea to begin with, but that aside, you could of course use something like

$animal = Animal::load(2);    // returns an instance of some subclass of Animal