php设计模式 数据对象映射模式，php设计模式
数据对象映射模式，是将对象和数据存储映射起来，对一个对象的操作会映射为对数据存储的操作。
在代码中实现数据对象映射模式，实现一个ORM类，将复杂的sql语句映射成对象属性的操作。对象关系映射（Object Relational Mapping，ORM）
ha_cl表
Hacl.php
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<?<span>php
namespace Baobab;
</span><span>class</span><span> Hacl{
</span><span>public</span> <span>$id</span><span>;
</span><span>public</span> <span>$haclname</span><span>;
</span><span>public</span> <span>$haclcode</span><span>;
</span><span>public</span> <span>$hacls</span><span>;
</span><span>protected</span> <span>$db</span><span>;<br /></span>
<span>function</span> __construct(<span>$id</span><span>){
</span><span>$this</span>->db = <span>new</span><span> \Baobab\Database\Mysqli();
</span><span>$this</span>->db->connect('127.0.0.1', 'root', '', 'test'<span>);
</span><span>$res</span> = <span>$this</span>->db->query("select * from ha_cl where id = {<span>$id</span>}"<span>);
</span><span>$data</span> = <span>$res</span>-><span>fetch_assoc();
</span><span>$this</span>->id = <span>$data</span>['ID'<span>];
</span><span>$this</span>->haclname = <span>$data</span>['ha_cl_name'<span>];
</span><span>$this</span>->haclcode = <span>$data</span>['ha_cl_code'<span>];
</span><span>$this</span>->hacls = <span>$data</span>['hacls'<span>];
}
</span><span>function</span><span> __destruct(){
</span><span>$this</span>->db->query("<span>update ha_cl set
ha_cl_code = '{</span><span>$this</span><span>->haclcode}',
ha_cl_name = '{</span><span>$this</span><span>->haclname}',
hacls = '{</span><span>$this</span><span>->hacls}'
where ID = {</span><span>$this</span><span>->id}
limit 1</span>"<span>);
}
}</span>
Factory.php
<?<span>php
namespace Baobab;
</span><span>class</span><span> Factory{
</span><span>static</span> <span>function</span> getHacl(<span>$id</span><span>){
</span><span>$key</span> = 'user_'.<span>$id</span><span>;
</span><span>$user</span> = \Baobab\Register::get(<span>$key</span><span>);//表中id不同表示的是不同的对象
</span><span>if</span>(!<span>$user</span><span>){
</span><span>$user</span> = <span>new</span> \Baobab\Hacl(<span>$id</span><span>);
\Baobab\Register</span>::set(<span>$key</span>, <span>$user</span><span>);
}
</span><span>return</span> <span>$user</span><span>;
}
}</span>
Register.php
<?<span>php
namespace Baobab;
</span><span>class</span><span> Register{
</span><span>protected</span> <span>static</span> <span>$objects</span><span>;
</span><span>static</span> <span>function</span> set(<span>$alias</span>, <span>$object</span><span>){
self</span>::<span>$objects</span>[<span>$alias</span>] = <span>$object</span><span>;
}
</span><span>static</span> <span>function</span> _unset(<span>$alias</span><span>) {
</span><span>unset</span>(self::<span>$objects</span>[<span>$alias</span><span>]);
}
</span><span>static</span> <span>function</span> get(<span>$name</span><span>) {
</span><span>return</span> self::<span>$objects</span>[<span>$name</span><span>];
}
}</span>
index.php
<span>class</span><span> Page{
</span><span>function</span><span> index(){
</span><span>$hacl</span> = Baobab\Factory::getHacl(13<span>);
</span><span>$hacl</span>->haclname = '测试名称'<span>;
</span><span>$this</span>-><span>test();
</span><span>echo</span> 'ok'<span>;
}
</span><span>function</span><span> test(){
</span><span>$hacl</span> = Baobab\Factory::getHacl(13<span>);
</span><span>$hacl</span>->hacls = '测试内容'<span>;
}
}
</span><span>$page</span> = <span>new</span><span> Page();
</span><span>$page</span>->index();
使用工厂模式会多次创建对象Hacl，浪费资源，如果将对象作为参数传递，一方面会带来额外的使用成本，另外如果很多地方都用到这个对象很容易发生错误，因此在工厂模式中使用注册树模式来解决这个问题。
