php 设计模式-数据映射模式（应用程序与数据库交互模式）

<?php
/**
 * Filename:db.class.php
 * 
 * db class ,use PDO lib
 * 
 * @author guisu.huang
 * @version 1.0
 * 
 */
class Db {
    public static $db = null;
    private $_dbh = null;
    public static function getInstance()
    {
        if( self::$db == null ){
            self::$db = new self(BACKEND_DBHOST ,BACKEND_DBUSER ,BACKEND_DBPW ,BACKEND_DBNAME);
        }
        return self::$db;
 
    }
 
    private function __construct( $host ,$user ,$pass ,$dbname ){
        try {
            $this->_dbh = new PDO('mysql:dbname='.$dbname.';host='.$host,$user,$pass);
            $this->_dbh->query('SET NAMES '. BACKEND_DBCHARSET);
            $this->_dbh->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true);
            $this->_dbh->setAttribute(PDO::ATTR_ERRMODE, true);
        } catch (PDOException $e) {
            throw new Exception('Can not connect db');
        }
    }
 
    private function getExecuteResult($sql, $sth){
        $type = strtolower(substr(trim($sql), 0,6));
        switch ($type) {
            case 'update': case 'delete':
                $result = $sth->rowcount();//返回影响的行数
            break;
            case 'insert':
                $result = $this->getLastId();
                break;
            case 'select':
                $result = $sth->fetchAll(PDO::FETCH_ASSOC);
                break;
            default:
                break;
        }
        return $result;
    }
    
    /**************************************sql ************************/
    
    public function getOne($sql){
        try {
            $rs = $this->_dbh->query($sql);
            $result = $rs->fetch(PDO::FETCH_ASSOC);
            if(!empty($result)) {
                return $result;
            }
        } catch (PDOException $e) {
            throw new Exception($this->_dbh->errorInfo());
        }
        return false;
    }
 
    public function getAll($sql){
        try {
            $rs = $this->_dbh->query($sql);
            $result = $rs->fetchAll(PDO::FETCH_ASSOC);
            if(!empty($result)) {
                return $result;
            }
        } catch (PDOException $e) {
            throw new Exception($this->_dbh->errorInfo());
        }
        return false;
    }
 
    public function exec($sql){
        try {
            $exec = $this->_dbh->exec($sql);
        } catch (PDOException $e){
            throw new Exception($this->_dbh->errorInfo());
        }
        return $exec;
 
    }
    /**
     * 不关注键值
     *  Execute a prepared statement by passing an array of values 
        $sth = $dbh->prepare('SELECT name, colour, calories
            FROM fruit
            WHERE calories < ? AND colour = ?');
        $sth->execute(array(150, 'red'));
        $red = $sth->fetchAll();
        $sth->execute(array(175, 'yellow'));
        $yellow = $sth->fetchAll();
     * @param unknown_type $sql
     * @param unknown_type $ar
     * @return unknown
     */
    public function executeArr($sql, $arr){
        try {
            $sth = $this->_dbh->prepare($sql);
            $r = $sth->execute($arr);
            if ($r) {
                return  $this->getExecuteResult($sql, $sth);
            }
        } catch (PDOException $e){
            throw new Exception($e->getMessage() . $this->_dbh->errorInfo());
        }    
    }
    /**
     * 关联数组:
     *  Execute a prepared statement by passing an array of values 
            $sql = 'SELECT name, colour, calories
            FROM fruit
            WHERE calories < :calories AND colour = :colour';
        $sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
        $sth->execute(array(':calories' => 150, ':colour' => 'red'));
        $red = $sth->fetchAll();
     *
     * @param unknown_type $sql
     * @param unknown_type $ar
     * @return unknown
     */
    public function executeAsoc($sql, $arr){
        try {
            $array = array();
            if ($arr) {
                foreach ($arr as $key=>$v) {
                    if (strpos($sql, ':' . $key )!==false) {
                        $array[':' . $key] = $v;
                    }
                }
            }
            $sth = $this->_dbh->prepare($sql);
            $r = $sth->execute($array);
            if ($r) {
                return  $this->getExecuteResult($sql, $sth);
            }
        } catch (PDOException $e){
            throw new Exception($e->getMessage() . $this->_dbh->errorInfo());
        }    
    }
    
    public function beginTransaction(){
        return $this->_dbh->beginTransaction();
    }
 
    public function commit(){
        return $this->_dbh->commit();
    }
 
    public function rollBack(){
        return $this->_dbh->rollBack();
    }
 
    public function getLastId()
    {
        return $this->_dbh->lastInsertId();
    }
 
    
    
}
 
?>

数据映相关类射类，使用__call达到动态生成getter 和setter方法.
<?php
/**
 * 抽象数据映射
 *
 */
abstract  class Table{
 
    public function __call($method, $args) {
        if (preg_match('/^(get|set)(\w+)/', strtolower($method), $match)
        && $attribute = $this->validateAttribute($match[2])) {
            if ('get' == $match[1]) {
                return $this->$attribute;
            } else {
                $this->$attribute = $args[0];
            }
        }else {
            throw new Exception(
            'Call to undefined method ' . __CLASS__  . '::'.$method.'()');
        }
    }
 
    protected function validateAttribute($method) {
        if ( in_array(strtolower($method), array_keys(get_class_vars(get_class($this))))) {
            return strtolower($method);
        }
 
    }
    
    
}
 
/**
 * 数据映射到表
 * 一般根据表的结构由工具自动生成，
 * 要不然程序员经常得copy和修改这个类
 *
 */
class UserTable extends Table {
    /**
     * fields
     *
     * @var unknown_type
     */
    protected $uid = null;
 
    protected $username = null ;
 
    protected $level = null;
 
    protected $exp = null;
 
    protected $ctime = null;
 
    protected $mtime = null;
    /**
     * table 
     *
     * @var unknown_type
     */
    public   $tableName = 'user';
 
    public  $primaryKey = 'uid';
    
    public  static $tablefileds = array(
                        'uid',
                        'username',
                        'level',
                        'exp',
                        'ctime',
                        'mtime',
    );
    
    /**
     * 对象生成数组
     *
     * @return array
     */
    function toArray(){
        $arr = array();
        foreach (UserTable::$tablefileds as $filed) {
            $getMethod  = 'get' .ucwords($filed);
            $value = $this->$getMethod();
            if ($value !== null) {
                $arr[$filed] = $value;
            }
        }
        return $arr;
    }
    
    /**
     * 数组生成对象
     *
     * @return array
     */
    function toObj($arr){
        if (!$arr) {
            return $this;
        }
        foreach (UserTable::$tablefileds as $filed) {
            $setMethod  = 'set' .ucwords($filed);
            $this->$setMethod($arr[$filed]);
        }
        return $this;
    }
}
 
/**
 * 
 *
 */
class Mapper{
    
    protected  $conn = null;
    
    /**
     * 自动插入
     * 不想对某一列插入，把对应的属性设置成null就ok
     *
     * @param Table $table
     * @return unknown
     */
    function save(Table $table){
        $arr  =  $table->toArray();
        $set = '';
        if ($arr) {
            foreach ($arr as $field=> $v) {
                if ($set) $set .=',';
                $set .= $field . "='" . $v ."'";
            }
        }
        if ($set) {
            $this->conn->exec( 'insert into ' . $table->tableName . ' SET ' . $set);
            return $this->conn->getLastId();
        }
        
        
    }
    
    /**
     * 更新
     * 不想对某一列更新，把对应的属性设置成null就ok
     *
     * @param Table $table
     * @return unknown
     */
    function update(Table $table){
        $arr  =  $table->toArray();
        $set = '';
        if ($arr) {
            foreach ($arr as $field=> $v) {
                if ($set) $set .=',';
                $set .= $field . "='" . $v ."'";
            }
        }
        $primayGet = 'get'.ucwords($table->primaryKey);
        if ($set) {
            return $this->conn->exec( 'update ' . $table->tableName . ' SET ' . $set . ' where ' . $table->primaryKey ."='" . $table->$primayGet() . "'" );
        }
    }
 
    
}
class UserMapper extends Mapper {
    
    const INSERT_SQL = "insert into user (username, level,exp, ctime, mtime) values (:username, :level, :exp, now(), now())";
    const UPDATE_SQL = "update user SET username=:username, level=:level, exp=:exp WHERE uid=:uid ";
    const SELECT_SQL = "select * from user  WHERE uid=:uid ";
    const DELETE_SQL = "delete from user  WHERE uid=:uid ";
    
    function __construct(){
        $this->conn =  Db::getInstance();
    }
    /**
     * 我们可以实现覆盖save
     *
     * @param unknown_type $userTable
     */
    public function save2($userTable) {
        $rs =  Db::getInstance()->executeArr( self::INSERT_SQL, $userTable->toArray());
        return $rs;
    }
    
    /**
     * Enter description here...
     *
     * @param unknown_type $userTable
     */
    public function update2($userTable) {
        return $this->conn->execute(self::UPDATE_SQL, $userTable->toArray());
    }
    
    /**
     * Enter description here...
     *
     * @param unknown_type $ar
     */
    public function find($userTable) {
        $rs = $this->conn->executeAsoc( self::SELECT_SQL, $userTable->toArray());
        return $rs ? $userTable->toObj($rs[0]) : $userTable;
    }
}
 
 
?>

实际客户测试：
<?php
 
/**
 * 数据库配置文件
 *
 */
define('BACKEND_DBHOST', 'localhost');
define('BACKEND_DBUSER', 'root');
define('BACKEND_DBPW', '123456');
define('BACKEND_DBNAME', 'sample');
define('BACKEND_DBCHARSET', 'utf-8');
 
//sql
/*
CREATE TABLE IF NOT EXISTS `user` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(64) NOT NULL,
  `level` int(11) NOT NULL DEFAULT '0',
  `exp` int(11) NOT NULL DEFAULT '0',
  `ctime` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
  `mtime` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  PRIMARY KEY (`uid`),
  KEY `username` (`username`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=12 ;
*/
 
class client{
    static function main(){
        $userMapper = new UserMapper();
        $user = new UserTable();
        //插入
        //$user->setUserName('guisu');
        //$user->setLevel(1);
        //$user->setExp(10);
        //
        //$userMapper = new UserMapper();
        //$r = $userMapper->save($user);
        
        //查找
        $user->setUid(10);
        $user = $userMapper->find($user);
        var_dump($user);
        //更新
        $user->setUserName('guisu2');
        $r = $userMapper->update($user);
        var_dump($r);
    }