php里ezpdo orm框架初探

下载解压.....

php默认内嵌sqlite3,修改config.ini:

default_dsn = sqlite3://books.db

我们讲解下examples/books这个项目,.在books子目录下,有两个子目录，分别是classes目录和complied目录,

其中classes 子目录是放类文件的,compiled目录是放ezpdo自己生成的文件,要求该目录要有写权限,
books.
   接下来我们设计实体类.这里以作者和其著作来说明,一个作者可以写多本书,一本书可以由多个
作者合写,构成典型的多对多关系了,先看一个基类

class Base {
    
    /**
     * tracking id (used by bookstore)
     * @var string
     * @orm char(64)
     */
    public $trackId;
    
    /**
     * Constructor
     */
    public function __construct() { 
        $this->trackId = uniqid('track-'); 
    } 
}

  这里没啥的,构造一个序列号而已,留意这里的注释了, @orm char(64),说明映射到数据库是string类型
,64位的,这有点象JAVA里JPA最新的anooatation的标记了，十分方便

接着是Author 类
 

 class Author extends Base {
    /**
     * Name of the author
     * @var string
     * @orm char(64)
     */
    public $name;
    
    /**
     * Books written by the author
     * @var array of Book
     * @orm has many Book
     */
    public $books = array();
    
    /**
     * Constructor
     * @param string $name author name
     */
    public function __construct($name = '') { 
        parent::__construct();
        $this->name = $name;
    }
 
    // the rest of the code in the class omitted... 
 
}

要留意的是$books是一个数组,因为一个作者有多本著作,而@orm has many Book则表明,一个作者
类关联到多个book类,而其中的关联等都不用我们搞了,也不象hibernate那样去设置.hbm配置文件了.
   再来看book类

class Book extends Base {

    /**
     * Bool title
     * @var string
     * @orm title char(80)
     */
    public $title;
    
    /**
     * Number of pages
     * @var integer
     * @orm integer
     */
    public $pages = -1;
    
    /**
     * Book author (assuming many co-authors)
     * @var Author
     * @orm has many Author
     */
    public $authors = array();
 
    /**
     * Constructor
     * @param string
     */
    public function __construct($title = '') { 
parent::__construct();
        $this->title = $title;
    }
 
    // the rest of the code in the class omitted... 
}

 可以看到,book类和author类差不多,也通过@orm has many Author类进行设置了关联
  好了，接下来我们可以开始设置一个add.php的文件里,用来给数据库增加数据,在目录里是add.php文件
首先要把ezpdo的类库API包含进来
     include_once ( dirname ( __FILE__ ) .  '/../../ezpdo_runtime.php' );
   // get the persistence manager (a singleton)
   $m = epManager:: instance ( );
 这里获得持久管理器类的实例了,有点象hibernate的sessionfactory,接着
我们创建作者类的实例了

  // create authors
 $a1 = $m->create('Author');
 $a1->name = 'Erich Gamma';
$a2 = $m->create('Author');
$a2->name = 'Richard Helm';
$a3 = $m->create('Author');
$a3->name = 'Ralph Johnson';
$a4 = $m->create('Author');
$a4->name = 'John Vlissides';

  我们创建了4个作者了
   如果你习惯了java的getter/setter,也可以这样

// setter 
$a1->setName('Erich Gamma');
// getter
echo $a1->getName();
  但是这不是必要的，因为在实体类里,你可以不必写getter/setter,ezpdoZ会帮你自动搞好,这点比hibernate要强些哦,
    接下来是书本类
// create books 
$b1 = $m->create('Book');
$b1->title = 'Design Patterns';
$b1->pages = 395;
 
$b2 = $m->create('Book');
$b2->title = 'Contributing to Eclipse: Principles, Patterns, and Plugins';
$b2->pages = 320;
   最后是把Author类和Books类关联起来
// add authors to books 
$b1->authors = array($a1, $a2, $a3, $a4);
$b2->authors = array($a1);
$b3->authors = array($a2);
$b4->authors = array($a3);
$b5->authors = array($a4);
 
// add books to authors 
$a1->books = array($b1, $b2);
$a2->books = array($b1, $b3);
$a3->books = array($b1, $b4);
$a4->books = array($b1, $b5);

  最后,提交到数据库
$m->flush();(要注意的是,如果config.inc里设置了auto_flush,则不用写这句话了)
    如果我们运行add.php后,再运行print.php,可以看到数据库中的确建立了3个表,一个是books表，一个是
author表，另一个是自动生成的用来做多对多的关联表了.

   要把对象状态提取出来，也很容易

// get the persistence manager
$m = epManager::instance();
 
// get all authors and books 
$authors = $m->get('Author');
$books = $m->get('Book');

查找对象也很容易,比如找Eric Gamma写的说,如下

// get the persistence manager
$m = epManager::instance();
 
// create the example object
$ea = $m->create('Author');
 
// set name to search
$ea->name = 'Erich Gamma'; 
 
// null variable is ignored in searching
// !!!important if the class constructor set non-null values!!!
$ea->trackId = null;
$ea->books = null;
 
// use the example object to find
if (!($as = $m->find($ea))) {
echo "Cannot find author [" . $ea->name . "]/n";
exit();
}
 
// go through each author and print
foreach($as as $a) {
echo $a; echo "/n";
}

甚至可以用象HIBERNATE中的HQL语句写,这里成了EZPDO SQL了,呵呵

// use EZOQL to find objects
$as = $m->query("from Author as author where author.name = 'Erich Gamma'");
if (!$as) {
echo "Cannot find author [Erich Gamma]/n";
exit();
}