PHP在数据库中查询Session_ID

Question

我一直在尝试在我的网站上查找会话 ID，以便我可以使用它来查询我的 MySQL 数据库，但我不断收到错误“未定义变量：_SESSION in...”

这是我的代码：

if (mysql_num_rows(mysql_query("SELECT * FROM users WHERE _id = " . $_SESSION['_id_of_user'])))

这里是我定义会话 ID 的地方：

$qry = "Select name, email, username, _id from $this->tablename where username='$username' and password='$pwdmd5' and confirmcode='y'";

$result = mysql_query($qry,$this->connection);

if(!$result || mysql_num_rows($result) <= 0)
{
    $this->HandleError("Error logging in. The username or password does not match");
    return false;
}

$row = mysql_fetch_assoc($result);

$_SESSION['name_of_user']     = $row['name'];
$_SESSION['email_of_user']    = $row['email'];
$_SESSION['username_of_user'] = $row['username'];
$_SESSION['_id_of_user']      = $row['_id'];

Answer 1

您必须在 sql 查询之前启动会话： http://us.php.net/manual/en/function.session-start.php

session_start();

然后你应该得到当前会话ID： http://us.php.net/manual/en/function.session-id.php

$current_session_id = session_id();

Answer 2

在尝试写信之前，你会先写一个session_start() 吗？ 也试试放

var_dump("<PRE>", $_SESSION);

在您尝试从中读取以查看其中实际内容之前。 所以你会：

session_start();
$_SESSION['name_of_user']     = $row['name'];
$_SESSION['email_of_user']    = $row['email'];
$_SESSION['username_of_user'] = $row['username'];
$_SESSION['_id_of_user']      = $row['_id'];

和：

var_dump("<PRE>", $_SESSION);
$qry = "Select name, email, username, _id from $this->tablename where username='$username' and password='$pwdmd5' and confirmcode='y'";

我也想知道你是否可以使用 $this->tablename 来做到这一点：

$qry = "Select name, email, username, _id from $this->tablename where username='$username' and password='$pwdmd5' and confirmcode='y'";

试试：

 $qry = "Select name, email, username, _id from ".$this->tablename." where username='$username' and password='$pwdmd5' and confirmcode='y'";