本文实例讲述了php数据对象pdo操作技巧。分享给大家供大家参考，具体如下：
php 数据对象 （pdo） 扩展为php访问数据库定义了一个轻量级的一致接口。
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<?php try { $dsn = "mysql:host=localhost; port=3306; dbname=wsq_hotel; charset=utf-8"; $user = 'root'; $psw ='root'; $pdo = new pdo($dsn,$user,$psw); $sql = 'select goods_prices from wsq_goods_info where goods_id=2'; // $sql = "show database"; $res = $pdo->query($sql) or var_dump($pdo->errorinfo()); // var_dump($res); $mon = $res->fetch(pdo::fetch_assoc); echo $mon['goods_price']; } catch (pdoexception $e) { echo $e->getmessage(); }?> |
pdo操作事务
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//开启事务begintransacition()//回滚rollback()//提交commit()//判断是否处于事务之中intransaction() |
返回最后插入行的id
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pdo::lastinsertid() |
exec()执行
与query()相比，exec()返回的是受影响行数
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$sql = "insert into table values('$val')";if(false===$pdo->exec($sql)){ echo '执行失败';} |
pdo实现预编译
指的是预先编译sql的结构的一种执行sql的语法
如果执行多条结构相同的sql，编译的中间结果（语法树）应该也是一致的，因此可以将相同的结构，统一编译，每次使用不同的数据执行即可。
编译统一的结构
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$pdostatement = $pdo->prepare(sql结构) |
绑定数据到中间编译结果
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$pdostatement ->bindvalue() |
执行
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$pdostatement ->execute()//$sql = "insert into table values(null,?)";$sql = "insert into table values(null,:name)";$stmt = $pdo->prepare($sql);//多组数据也是一编译一执行//$stmt->bindvalue(1,'bee');$stmt->bindvalue(':name','bee');$res = $stmt->execute();var_dump($res); |
预编译能更好地防止sql注入，是因为预编译时候不需要用户的数据参与，因此编译时结构固定，所以数据不影响到sql结构。
$pdo->query()与$pdo->execute()如果需要防止sql注入，可以使用$pdo->quote()(其作用是先转义后加引号)
pdostatement常用方法：
errorinfo()
errorcode()
fetchcolumn()
fetch()
fetchall()
rowcount()
closecursor()
pdo应用
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<?phpheader('content-type:text/html;charset=utf-8'); class pdodb{ static private $_init; private $_host; private $_port; private $_dbname; private $_username; private $_password; private $_charset; private $_dns; private $_pdo; private function __construct($config){ $this->_initparamas($config); $this->_initdns(); $this->_initdriveroptions(); $this->_initpdo(); } private function __clone(){} static public function getinstance($config){ if(!static::$_init instanceof static){ static::$_init = new static($config); } return static::$_init; } private function _initparamas($config){ $this->_host = isset($config['host'])?$config['host']:'localhost'; $this->_port = isset($config['port'])?$config['port']:'3306'; $this->_dbname = isset($config['dbname'])?$config['dbname']:''; $this->_username = isset($config['username'])?$config['username']:'root'; $this->_passward = isset($config['passward'])?$config['passward']:''; $this->_charset = isset($config['charset'])?$config['charset']:'utf8'; } private function _initdns(){ $this->_dns = "mysql:host=$this->_host;port=$this->_port;dbname=$this->_dbname"; } private function _initdriveroptions(){ $this->_driveroptions = array( pdo::mysql_attr_init_command => "set names $this->_charset" ); } private function _initpdo(){ $this->_pdo = new pdo($this->_dns,$this->_username,$this->_passward,$this->_driveroptions) or die("fail"); } public function query($sql){ if(!$result = $this->_pdo->query($sql)){ $erro = $this->_pdo->errorinfo(); echo '失败的语句'.$sql.'<br>'; echo '错误代码'.$erro[1].'<br>'; echo '错误信息'.$erro[2].'<br>'; die; } return $result; } public function fetchall($sql){ $res = $this->query($sql); $list = $res->fetchall(pdo::fetch_assoc); $res->closecursor(); return $list; } public function fetchrow($sql){ $res = $this->query($sql); $row = $res->fetch(pdo::fetch_assoc); $res->closecursor(); return $row; } public function fetchone($sql){ $res = $this->query($sql); $one = $res->fetchcolumn(); $res->closecursor(); return $one; } public function escape_string($data){ return $this->_pdo->quote($data); } } $config = array( "host"=>"localhost", "username"=>"root", "passward"=>"root", "dbname"=>"students" ); $pdo = pdodb::getinstance($config); $sql = "select sdept from student where sage=21"; var_dump($pdo->fetchrow($sql));?> |
运行效果图如下：
希望本文所述对大家php程序设计有所帮助。
