在PHP中更有效地使用类？

Question

Okay, let's say I two files and a MySQL table called Users and a table called Select .

• index.php
• fucntions.php

Users

 ID NAME L_NAME POINTS 0 Jill Jackson 10 1 Jack Wills 90 2 John Doe 30 

Select

 ID OPTION 0 Points 1 Name 2 LastName 

index.php contains a simple table and select like so.

<?php include 'output.php'; ?>

<h3>Sort by: </h3>

<select>
  <?php getSelect(); ?>
</select>

<table>
  <tr>
    <th>Firstname</th>
    <th>Lastname</th> 
    <th>Points</th>
  </tr>
  <tr>
  <?php outputData(); ?>
  </tr>
</table>

My fucntions.php file has the following code:

function outputData() {
    try {
        $handler = new PDO("mysql:host=$host;dbname=$db", "$user", "$pass");
        $handler->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch (PDOException $e)
     {
        echo $e->getMessage();
        echo 'Sorry, an error has occurred.';
        die();
     }

    $query = $handler->query('SELECT * FROM `Users`');

    while($r = $query->fetch(PDO::FETCH_OBJ)) {
    echo
        '
            <td>
                <input type="text" value="'.$r->Name.'" >
            </td>
            <td>
                <input type="text" value="'.$r->l_name.'">
            </td>
            <td>
                <input type="text" value="'.$r->points.'">
            </td>
        ';
    }
}

function getSelect() {
    try {
        $handler = new PDO("mysql:host=$host;dbname=$db", "$user", "$pass");
        $handler->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch (PDOException $e)
     {
        echo $e->getMessage();
        echo 'Sorry, an error has occurred.';
        die();
     }

    $query = $handler->query('SELECT * FROM `Select`');

    while($r = $query->fetch(PDO::FETCH_OBJ)) {
    echo
        '
            <li>'.$r->option.'</li>
        ';
    }
}

I would be using this code to output data onto multiple different pages. This is just a very basic example... I have multiple different functions for outputting and inserting data from tables. My question is, would using classes be a better option than just writing bare functions like I have here and including it on every page I need?

What are the benefits of using a class vs what I'm currently doing?

I have looked at various tutorials of how to construct classes but I've never actually found the real need as to what the benefit is when compared to what I'm doing currently...

Could someone elaborate?

Answer 1

To me the main need for using classes, at least in the scenario you gave, is to help to

• the readability of the code. Code is much more readable using objects that represent something in the real life, also, you don't mess all the functions into one or several files. If a function affects one class (fi uses its class members, despite this is very relative), you know that that class.php is where you should create that function and where you should find it.

• the maintainability of the code. For the same reason, code is much more maintainable. You know what an object is supposed to do, you read easily what your code should do and where. This helps, imho debugging. Also, when you are programming you in a way more intuitive know which data goes into a class and which method of that object which contains that data can be used.

• encapsulation. This concept entails more effort when programming because you have to take care about which members should be accessible by other instances of other classes or main code but can prevent lots of mistakes. For instance,could prevent cases where you are debugging and you expect a value for a variable which doesn't correspond with what really is happening... and all because there is a piece of code somewhere which changed that value and you didn't even realize.

• reusability. Your classes could be useful in other projects with a few changes (and easy to locate where and what you need to change)

For sure there should be many more reasons, but those are the main coming to my head. BTW, using procedural programming can be easier, faster and even cleaner in small projects or parts of the project.