PDO基础

//PDO:数据访问抽象层

$dsn = "mysql:dbname=mydb;host=localhost";//造PDO对象
$pdo = new PDO($dsn,"root","123");

//写SQL语句
$sql = "select * from bookname_w";
$stm = $pdo->query($sql);//执行SQL查询语句,返回PDOSTATEMENT对象

$sql = "update bookname_w set bookname='php1' where id=o";
$arr = $pdo->exec($sql);//执行SQL增删改语句

//读数据
$arr = $stm->fetch(PDO::FETCH_NUM);
$arr = $stm->fetchAll(PDO::FETCH_ASSOC);
var_dump($arr);

//事务功能 同时修改，有错误都不做修改

$dsn = "mysql:dbname=mydb;host=localhost";
$pdo = new PDO($dsn,"root","123");

//把PDO的错误模式设置为异常模式
$pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);

//捕获异常
try
{
	//开启事务功能
	$pdo->beginTransaction();

	$sql1 = "insert into bookname_w values('','css')";
	$sql2 = "insert into bookname_w values('','dw')";
	$sql3 = "insert into bookname_w values('','java')"; 

	$pdo->exec($sql1);
	$pdo->exec($sql2);
	$pdo->exec($sql3);

	//提交事务
	$pdo->commit();
}
catch(Exception $e)
{
	//捕获异常并解决异常
	//回滚
	$pdo->rollBack();
	//var_dump($e);
}