数据库抽象层 pdo

　　$host = "localhost";
$dbname = "hejuntest";
$username = "root";
$pwd = "";
$dsn = "mysql:host=$host;dbname=$dbname";
$opt = array(PDO::ATTR_PERSISTENT => TRUE);  //持久链接
try{
$pdo = new PDO($dsn , $username , $pwd , $opt);
}catch(PDOException $e){
echo 'connect error~ ' . $e->get_Message();
}

$sql = "update student set name='xiaoran' where id in(1,2) ";
$affted_rows = $pdo->exec($sql);  //返回受影响的行数

$sql = "select * from student";
$pdostatement = $pdo->query($sql);
echo '<table>';
while(list($id , $name , $age , $class) = $pdostatement->fetch(PDO::FETCH_NUM)){
echo '<tr>';
echo '<td>' . $id .'</td>';
echo '<td>' . $name .'</td>';
echo '<td>' . $age .'</td>';
echo '<td>' . $class .'</td>';
echo '</tr>';
}
echo '</table>';

$sql = "select * from student";
$pdostatement = $pdo->query($sql);
$data = $pdostatement->fetchAll(PDO::FETCH_ASSOC);
echo '<table>';
foreach($data as $k => $v){
echo '<tr>';
echo '<td>' . $v['id'] .'</td>';
echo '<td>' . $v['name'] .'</td>';
echo '<td>' . $v['age'] .'</td>';
echo '<td>' . $v['class'] .'</td>';
echo '</tr>';
}
echo '</table>';

$sql = "insert into student (name,age,class) values (:name,:age,:class)";
$pdostatement = $pdo->prepare($sql);

$pdostatement->bindParam(":name" , $name);
$pdostatement->bindParam(":age" , $age);
$pdostatement->bindParam(":class" , $class);
$name = "hejun";
$age = 25;
$class = 15;
$pdostatement->execute();

$name = "daxi";
$age = 26;
$class = 16;
$pdostatement->execute();

　　 $sql = "insert into student(name,age,class) values(?,?,?)";
$pdostatement = $pdo->prepare($sql);

$pdostatement->bindParam(1 , $name);
$pdostatement->bindParam(2 , $age);
$pdostatement->bindParam(3 , $class);

$name = "hejun";
$age = 25;
$class = 15;
$pdostatement->execute();

$name = "daxi";
$age = 26;
$class = 16;
$pdostatement->execute();

$sql = "insert into student(name,age,class) values(?,?,?)";
$pdostatement = $pdo->prepare($sql);
$pdostatement->execute(array("daxixi",20,11));

echo $pdo->lastInsertId(); //如果有主键，得到最后一条插入的主键值

echo '<br>' . $pdostatement->rowCount();//得到影响行数