Php中使用PDO操作MySQL数据库(查询 更新 删除)

header("content-type:text/html;charset=utf-8");

$dsn="mysql:dbname=test;host=localhost";
$db_user='root';
$db_pass='admin';

try{
 $pdo=new PDO($dsn,$db_user,$db_pass);
}catch(PDOException $e){
 echo '数据库连接失败'.$e->getMessage();
}

//新增
$sql="insert into buyer (username,password,email) values ('ff','123456','admin@admin.com')";
$res=$pdo->exec($sql);
echo '影响行数：'.$res;

//修改
$sql="update buyer set username='ff123' where id>3";
$res=$pdo->exec($sql);
echo '影响行数：'.$res;

//查询
$sql="select * from buyer";
$res=$pdo->query($sql);

foreach($res as $row){
 echo $row['username'].'
';
}

//删除
$sql="delete from buyer where id>5";
$res=$pdo->exec($sql);
echo '影响行数：'.$res;