php连接mysql数据库

搞好php,就想把原来在java那部分学的东西往php上套下试试，没有建表，直接使用mysql自带的数据库表。代码如下

exec("set names 'utf8'");
    $pdoStatement=$pdo->prepare($sql);
    $pdoStatement->execute((array($user)));
    $pdoStatement->bindColumn('host', $host);
    $pdoStatement->bindColumn('user', $user);
    $pdoStatement->bindColumn('password', $password);
    while ($row = $pdoStatement->fetch(PDO::FETCH_BOUND)) {
       echo $host;
       echo "
";
       echo $user;
       echo "
";
       echo $password;
       echo "
";
    }
} catch (PDOException $e) {
    print $e->getMessage();
}
echo "end";