PHP OOP保存，将类属性获取到数据库

Question

I'm trying to learn oop. I'm working with PHP-MySQL. And I have troubles about database jobs with oop way (save, update, get etc.).

Let me explain it with an example project.

Lets say I want to make a site with multiple user types. I have a single database table with an enum "type" field. And I made classes like these:

abstract class User {
 //common properties, functions etc.. like id, username.
}

class Admin extends User {
 protected $type = "ADMIN";
 //I want here to have admin specific fields, functions etc...
}

...and some other user types like that. Here is the thing. I want a common class that can save and update objects into database. What's the way to do that? I'll make an object like $user = new User(); bla.. bla.. and I'll say "Save this user" but how? Do I have to make functions for each of my classes that have specific SQL statements like "INSERT INTO table(name, pass, etc) VALUES ('name', 'pass', etc)"?

Another point is I want a common factory class that returns me an object. An example I'll say "Get me the user which have this id and instantiate it with admin class if that user is an admin or the other classes like that".

And I need some help about "how to instantiate like mysqli_fetch_assoc() result with objects". That returns an array. Do I need to do like "$object->setId(returned_array["id"])"?

I've looked some books like PHP in Action, PHP Objects, Patterns and Practice but couldn't find this database specific topics. I hope I could explained it well and sorry for my bad English :)

Answer 1

I think you need an ORM framework. It's hard to create a good one on your own but you can find a few existing frameworks. Be carefulf do not use a framework with active record pattern becouse it's an antipattern.

To fetch objects: http://www.php.net/manual/en/mysqli-result.fetch-object.php

But I also recommend you to use mysqli in OO way:

$resource = new mysqli(/* ... */);
$resource->fetch_object(/* ... */)