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Quick Start with PHP Object-Oriented Programming_PHP Tutorial
- WBOYOriginal
- 2016-07-21 16:07:49795browse
Object-oriented programming (OOP) is a basic skill in our programming, and PHP4 provides good support for OOP. How to use OOP ideas to perform advanced programming of PHP is very meaningful for improving PHP programming capabilities and planning a good Web development architecture. Below we will use examples to illustrate the practical significance and application methods of using PHP's OOP for programming.
When we usually build a website with a database backend, we will consider that the program needs to be suitable for different application environments. What is different from other programming languages is that in PHP, a series of specific functions are used to operate the database (if you do not use the ODBC interface). Although this is very efficient, the encapsulation is not enough. If there is a unified database interface, then we can apply it to a variety of databases without making any modifications to the program, thus greatly improving the portability and cross-platform capabilities of the program.
To complete OOP in PHP, you need to encapsulate objects, that is, write classes. We can achieve a simple encapsulation of the database by generating a new SQL class. For example:
< ?
class SQL
{
var $Driver; //Actual database driver subclass
var $connection; //Shared database connection variables
function DriverRegister($d)
{
if($d!="")
{
$include_path = ini_get("include_path");
$DriverFile = $include_path ."/".$d.".php";
//The driver storage path must be under the INCLUDE_PATH set in the PHP.ini file
if( file_exists( $DriverFile)) // Find whether the driver is Exists
{
include($DriverFile);
$this->Driver = new $d();
// Generate the corresponding database driver class based on the driver name
return true;
}
}
return false; //Failed to register driver
}
function Connect($host,$user,$passwd,$database)//Function to connect to the database
{
$this->Driver->host=$host;
$this->Driver->user=$user;
$this->Driver->passwd=$ pas
swd;
$this->Driver->database=$d
atabase;
$this->connection = $this->Driver->Connect();
}
function Close()//Close database function
{
$this->Driver->close($this->connection);
}
function Query($queryStr)//Database string query function
{
return $this->Driver->query($queryStr,$this->connection);
}
function getRows($res)//Find the row
{
return $this->Driver->getRows($res);
}
function getRowsNum($res)//Get the row number
{
return $this->Driver-> getRowsNum ($res);
}
}
? >
We take operating the MySQL database as an example . We write a database driver class MySQL. In this class, we further encapsulate the functions related to MySQL database operations. Put the file containing this class and the file name is MySQL.php under the PHP system include_path, and it can be used normally. Note that when writing the database driver file, the file name should be consistent with the class name.
< ?
Class MySQL
{
var $host;
var $user;
var $passwd;
var $database;
function MySQL() //利用构造函数实现变量初始化
{
$host = "";
$user = "";
$passwd = "";
$database = "";
}
function Connect()
{
$conn = MySQL_connect($this->host, $this->user,$this->passwd) or
die("Could not connect to $this->host");
MySQL_select_db($this->database,$conn) or
die("Could not switch to database $this->database;");
return $conn;
}
function Close($conn)
{
MySQL_close($conn);
}
function Query($queryStr, $conn)
{
$res =MySQL_query($queryStr, $conn) or
die("Could not query database");
return $res;
}
function getRows($res)
{
$rowno = 0;
$rowno = MySQL_num_rows($res);
if($rowno>0)
{
for($row=0;$row<$rowno;$row++)
{
$rows[$row]=MySQL_fetch_row($res);
}
return $rows;
}
}
function getRowsNum($res)
{
$rowno = 0;
$rowno = mysql_num_rows($res);
return $rowno;
}
}
? >
同样我们要封装其他的“数据库驱动”到我们的SQL类中，只需要建立相应的类，并以同名命名驱动文件，放到PHP的include目录就可以了。
完成封装以后，就可以在PHP中按照OOP的思想来实现对数据库的编程了。
< ?
Include(“SQL.php”);
$sql = new SQL; //生成新的Sql对象
if($sql-> DriverRegister(“MySQL”)) //注册数据库驱动
{
$sql->Connect(“localhost”,”root”,””,”test”);
$res=$sql->query(“select * from test”); //返回查询记录集
$rowsnum = $sql->getRowsNum($res);
if($rowsnum > 0)
{
$rows = $sql->getRows($res);
foreach($rows as $row) //循环取出记录集内容
{
foreach($row as $field){
print $field;}
}
}
$sql->Close();
}
? >
在实际应用中，我们还可以根据实际需求对各种对象类做进一步扩展。在PHP中，还提供了一系列复杂的OOP方法，例如继承，重载，引用，串行化等等。充分调动各种方法并灵活运用，就能够使你的网站更合理和结构化，开发和维护也更容易。