如何实现MVC模式的PHP功能？
例子
这里是一个使用MVC模式的简单例子。
首先我们需要一个数据库访问类，它是一个普通类。
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/**
*A simple class for querying MySQL
*/
classDataAccess{
/**
* Private
* $db stores a database resource
*/
var$db;
/**
* Private
* $query stores a query resource
*/
var$query;// Query resource
//! A constructor.
/**
* Constucts a new DataAccess object
* @param $host string hostname for dbserver
* @param $user string dbserver user
* @param $pass string dbserver user password
* @param $db string database name
*/
functionDataAccess($host,$user,$pass,$db){
$this->db=mysql_pconnect($host,$user,$pass);
mysql_select_db($db,$this->db);
}
//! An accessor
/**
* Fetches a query resources and stores it in a local member
* @param $sql string the database query to run
* @return void
*/
functionfetch($sql){
$this->query=mysql_unbuffered_query($sql,$this->db);// Perform query here
}
//! An accessor
/**
* Returns an associative array of a query row
* @return mixed
*/
functiongetRow(){
if($row=mysql_fetch_array($this->query,MYSQL_ASSOC))
return$row;
else
returnfalse;
}
}
?> |
在它上边放上模型。
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/**
*Fetches "products" from the database
*/
classProductModel{
/**
* Private
* $dao an instance of the DataAccess class
*/
var$dao;
//! A constructor.
/**
* Constucts a new ProductModel object
* @param $dbobject an instance of the DataAccess class
*/
functionProductModel(&$dao){
$this->dao=&$dao;
}
//! A manipulator
/**
* Tells the $dboject to store this query as a resource
* @param $start the row to start from
* @param $rows the number of rows to fetch
* @return void
*/
functionlistProducts($start=1,$rows=50){
$this->dao->fetch("SELECT * FROM products LIMIT ".$start.", ".$rows);
}
//! A manipulator
/**
* Tells the $dboject to store this query as a resource
* @param $id a primary key for a row
* @return void
*/
functionlistProduct($id){
$this->dao->fetch("SELECT * FROM products WHERE PRODUCTID='".$id."'");
}
//! A manipulator
/**
* Fetches a product as an associative array from the $dbobject
* @return mixed
*/
functiongetProduct(){
if($product=$this->dao->getRow())
return$product;
else
returnfalse;
}
}
?> |
有一点要注意的是，在模型和数据访问类之间，它们的交互从不会多于一行——没有多行被传送，那样会很快使程式慢下来。同样的程式对于使用模式的类，它只需要在内存中保留一行（Row）——其他的交给已保存的查询资源（query resource）——换句话说，我们让MYSQL替我们保持结果。
接下来是视图——我去掉了HTML以节省空间，你可以查看这篇文章的完整代码。
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/**
*Binds product data to HTML rendering
*/
classProductView{
/**
* Private
* $model an instance of the ProductModel class
*/
var$model;
/**
* Private
* $output rendered HTML is stored here for display
*/
var$output;
//! A constructor.
/**
* Constucts a new ProductView object
* @param $model an instance of the ProductModel class
*/
functionProductView(&$model){
$this->model=&$model;
}
//! A manipulator
/**
* Builds the top of an HTML page
* @return void
*/
functionheader(){
}
//! A manipulator
/**
* Builds the bottom of an HTML page
* @return void
*/
functionfooter(){
}
//! A manipulator
/**
* Displays a single product
* @return void
*/
functionproductItem($id=1){
$this->model->listProduct($id);
while($product=$this->model->getProduct()){
// Bind data to HTML
}
}
//! A manipulator
/**
* Builds a product table
* @return void
*/
functionproductTable($rownum=1){
$rowsperpage='20';
$this->model->listProducts($rownum,$rowsperpage<SPAN lang=EN-US style="FONT-SIZE: 9pt; COLOR: #006600;
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