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 accessing 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);

?>