PHP中使用匿名函数操作数据库的例子

Base dao class illustrating the usefulness of closures.
Handles opening and closing of connections.
Adds slashes sql
Type checking of sql parameters and casts as appropriate
Provides hook for processing of result set and emitting one or more objects.
Provides hook for aessing underlying link and result objects.

<?php

define("userName","root");
define("password","root");
define("dbName","ahcdb");
define("hostName","localhost");

class BaseDao {

    function getConnection()    {
        $link = mysql_connect(hostName, userName, password);
        if (!$link)
            die("Could not connect: " . mysql_error());
        if (!mysql_select_db(dbName))
            die("Could not select database: " . mysql_error());
        return $link;
    }
   
    function setParams(& $sql, $params)    {
        if($params != null)
            $sql = vsprintf($sql, array_map(function($n) {
                if(is_int($n))
                    return (int)$n;
                if(is_float($n))
                    return (float)$n;
                if(is_string($n))
                    return "'".mysql_real_escape_string($n)."'";
                return mysql_real_escape_string($n);
            }, $params));
    }

    function executeQuery($sql, $params, $callback = null)    {
        $link  = $this->getConnection();
        $this->setParams($sql, $params);
        $return = null;
        if(($result = mysql_query($sql, $link)) != null)
            if($callback != null)
                $return = $callback($result, $link);
        if($link != null)
            mysql_close($link);
        if(!$result)
            die("Fatal Error: Invalid query '$sql' : " . mysql_error());
        return $return;
    }
 
    function getList($sql, $params, $callback)    {
        return $this->executeQuery($sql, $params, function($result, $link) use ($callback) {
            $idx = 0;
            $list = array();
            while ($row = mysql_fetch_assoc($result))
                if($callback != null)
                    $list[$idx] = $callback($idx++, $row);
            return $list;
        });
    }
   
    function getSingle($sql, $params, $callback)    {
        return $this->executeQuery($sql, $params, function($result, $link) use ($callback) {
            if ($row = mysql_fetch_assoc($result))
                $obj = $callback($row);
            return $obj;
        });
    }
}

class Example    {
    var $id;
    var $name;
   
    function Example($id, $name){
        $this->id = $id;
        $this->name = $name;
    }
   
    function setId($id){
        $this->id = $id;
    }
}

class ExampleDao extends BaseDao    {
   
   
    function getAll(){
        return parent::getList("select from nodes", null, function($idx, $row) {
            return new Example($row["id"], $row["name"]);
        });
    }
   
    function load($id){
        return parent::getSingle("select from nodes where id = %1\$s", array($id), function($row) {
            return new Example($row["id"], $row["name"]);
        });
    }
   
    function update($example){
        return parent::executeQuery("update nodes set name = '' where  id = -1", null, function($result, $link){
            return $result;
        });
    }
   
    function insert(& $example){
        return parent::executeQuery("insert into nodes", null, function($result, $link) use ($example){
            $id = mysql_insert_id($link);
            $example->setId($id);
            return $result;
        });
    }   
}

$exampleDao = new ExampleDao();

$list = $exampleDao->getAll());

$exampleObject = $exampleDao->load(1));

$exampleDao->update($exampleObject);

?>