php的PDO类中bindValue和bindParam的区别

// bindParam是绑定一个PHP变量到一个SQL参数.是引用方式传递

// 所以你可以改变变量值，再执行.就赋给SQL语句不同的值

// 注意与bindValue的区别

try {

$sql = 'UPDATE `pdo` set `user` = :user, `email` = :email WHERE `id` = :id';

$pre = $dbh->prepare($sql);

// 此处bindParam.执行一次更改id=2,执行一次更改id=3.结果不一样

$user = "ncat2";

$email = "ncat2@admpub.com";

$id = 2;

$pre->bindParam(':user', $user, PDO::PARAM_STR);

$pre->bindParam(':email', $email, PDO::PARAM_STR);

$pre->bindParam(':id', $id, PDO::PARAM_INT);

$pre->execute();

$user = "ncat3";

$email = "ncat3@admpub.com";

$id = 3;

$pre->execute();

unset($user, $email, $id);

// 此处bindValue. 执行两次id=4的SQL

$user = "ncat4";

$email = "ncat4@admpub.com";

$id = 4;

$pre->bindValue(':user', $user, PDO::PARAM_STR);

$pre->bindValue(':email', $email, PDO::PARAM_STR);

$pre->bindValue(':id', $id, PDO::PARAM_INT);

$pre->execute();

$user = "ncat5";

$email = "ncat5@admpub.com";

$id = 5;

$pre->execute();

} catch (PDOException $e)

{var_dump($e);}
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