Object-oriented Programming in PHP: How to develop a large PHP project (v) Author: Luis Argerich Translator: Limodou using classes for data storage a very good thing about PHP and OOP is that you can easily define a class to manipulate something, and whenever you want to You can call the appropriate class when you use it. Suppose you have an HTML form that allows users to select a product by selecting the Product ID number. In the database has the product information, you want to display the product, show its price and so on. You have different types of products, and the same action may have different meanings for different products. For example, displaying a sound might mean playing it, but for other kinds of products it might mean displaying a picture in the database. You can use OOP or PHP to reduce coding and improve quality: Define a product's class, define the method it should have (for example: Display), and then define the class for each type of product, from the product class to the Sounditem class, Viewableitem class, etc. Override the methods in the product class so that they act as you think. A typical product table may have (ID, type, price, description, and so on), depending on the type of each product in the database, given the class name. Then in the processing script, you can remove the type value from the database and instantiate an object named type:-------------------------------------------------------------------- ------------ Action ();?>--------------------------------------------------------------------------------This is a very good feature of PHP, You can call $obj's display method or other methods without having to consider the type of object. With this technique, you don't need to modify the script to add a new type of object, just add a class that handles it. This is a powerful feature, as long as you define the method without considering the types of all the objects, implement them in different ways, and then use them in the main script for any object, no if...else, no two programmers, only happy. Now do you agree that programming is easy, maintenance is cheap, reusable is true? If you manage a group of programmers, assigning jobs is easy, and everyone can be responsible for one type of object and the class that handles it. Internationalization can be achieved through this technology, according to the user's chosen language field to apply the corresponding class can be, and so on. Copy and clone when you create an $obj object, you can copy the object through the $obj2= $obj, and the new object is a copy of the $obj (not a reference), so it has a $obj state at the time. Sometimes, you don't want to, you just want to create a new object like the Obj class, you can call the class's constructor by using the new statement. It can also be implemented in PHP by serialization, and a base class, but all other classes are derived from the base class. Enter the hazardous area when you serialize an object, you get a string of some format, and if you're interested, you can tune it, where the string has the class name (great!). ), you can take it out, like this:-------------------------------------------------------------------------------- --------------------------------------------------------------------------------So suppose you have created a class of "Universe", and forcing all classes to be extended from universe, you can define a clone method in universe, as follows:---------------------------------------------------------- ---------------------- Clone ();?>-------------------------------------------------------------------------------- What you get is a new object of the Something class, which is the same as using the new method, which calls the constructor to create the object. I don't know if this is useful for you, but the Universe class can know the name of the derived class as a good experience. Imagination is the only limit. Note: I use PHP4, I write some things under PHP3 may not work. Transfer from phpbuilder.com
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