PHP 中的 session_unset() 和 session_destroy() 有什么区别？

What is the difference between session_unset() and session_destroy() in PHP?

提问by Johan

From the php.netdocumentation:

来自php.net文档：

session_destroy— Destroys all data registered to a session

session_unset— Free all session variables

session_destroy— 销毁注册到会话的所有数据

session_unset— 释放所有会话变量

My three part question is:

我的三部分问题是：

The two functions seem very similar.
What is really the difference between the two?

这两个功能看起来非常相似。
两者之间的真正区别是什么？

Both seem to delete all variables registered to a session. Does any of them actually destroy the session itself? If not, how do you accomplish this (destroy the session itself).

两者似乎都删除了注册到会话的所有变量。他们中的任何一个实际上破坏了会话本身吗？如果没有，您如何完成此操作（销毁会话本身）。

Is it correct that neither of the two functions deletes the session cookie at the client?

这两个函数都不删除客户端的会话 cookie 是否正确？

回答by Gumbo

session_unsetjust clears the $_SESSIONvariable. It's equivalent to doing:

session_unset只是清除$_SESSION变量。这相当于做：

$_SESSION = array();

So this does only affect the local $_SESSIONvariable instance but not the session data in the session storage.

所以这只会影响局部$_SESSION变量实例，而不影响会话存储中的会话数据。

In contrast to that, session_destroydestroys the session data that is stored in the session storage (e.g. the session file in the file system).

与此相反，session_destroy销毁会话存储中存储的会话数据（例如文件系统中的会话文件）。

Everything else remains unchanged.

其他一切都保持不变。

回答by Xamael

session_destroy();is deleting the whole session.

session_destroy();正在删除整个会话。

session_unset();deletes only the variables from session - session still exists. Only data is truncated.

session_unset();仅从会话中删除变量 - 会话仍然存在。只有数据被截断。

回答by SLyHuy

session_unset();

Just clear all data of all session variable.

只需清除所有会话变量的所有数据。

session_destroy();

Remove all session.

删除所有会话。

---

---

Example示例：

session_start();
session_destroy();     
$a = "1234";
$_SESSION[a] = $a;

$_SESSION[a]is NULL.

$_SESSION[a]是NULL。

session_start();
session_unset();     
$a = "1234";
$_SESSION[a] = $a;

$_SESSION[a]is 1234.

$_SESSION[a]是1234。

So, I will use:

所以，我将使用：

session_start();
session_destroy();   
session_start();  
$a = "1234";
$_SESSION[a] = $a;

回答by kaushik

session_unset()will clear the $_SESSIONvariable (as in array()), but it won't touch the session file. But when the script ends; the state of the $_SESSIONwill be written to the file. Then it will clear the file but won't delete it. When you use session_destroy()it won't touch $_SESSION(Use var_dump($_SESSION)after session_destroy()), but will delete the session file, so when script exits there won't be a file to write the state of the $_SESSION.

session_unset()将清除$_SESSION变量（如array()），但不会触及会话文件。但是当脚本结束时；的状态$_SESSION将写入文件。然后它会清除文件但不会删除它。当你使用session_destroy()它时不会接触$_SESSION（使用var_dump($_SESSION)之后session_destroy()），但会删除会话文件，所以当脚本退出时不会有一个文件来写入$_SESSION.

回答by Radian Yusuf Mahendra

session_destroy()will delete the session after moving the page and session_unset()will delete session when the code is run.

session_destroy()将在移动页面后 session_unset()删除会话，并在代码运行时删除会话。

回答by Marvin

I tried to use session_unset($_SESSION['session_name'])thinking it will only unset specific or individual/single session name. But using session_unset($_SESSION['session_name'])will only unset all session name. The right code to use is only unset($_SESSION['session_name'])if you want to unset a single session name.

我试图session_unset($_SESSION['session_name'])认为它只会取消设置特定或个人/单个会话名称。但是使用session_unset($_SESSION['session_name'])只会取消设置所有会话名称。仅unset($_SESSION['session_name'])当您想取消设置单个会话名称时才使用正确的代码。

回答by Yadab Sd

session_start(); #it will create an virtual array (associative) in browser realtime memory

session_start(); #它将在浏览器实时内存中创建一个虚拟数组（关联）

two item added

添加了两个项目

> $_SESSION['me'] = "Yadab";  
> $_SESSION['you'] = "Avi";
>
> print_r($_SESSION); #will give, array( "me"=>"Yadab", "you"=>"Avi" )

test1

测试1

> unset($_SESSION['me']); #only 'me' variable is removed fully (index & value) 
> print_r($_SESSION); #now the array is Array("you"=>"Avi")

test2

测试2

> session_destroy(); #will unset the values of all session variables, but indexes exists 
> print_r($_SESSION); #Output, Array("you"=>undefined)
> #but some browser can store the value in cookies

test3

测试3

> session_unset(); #will unset all the main variables not only the values 
> print_r($_SESSION); #that means session array is now empty, like Array()

test block 1, 2, or 3 at individually by comment out others

单独的测试块 1、2 或 3 通过注释掉其他

回答by Riaj Mahmud Rasel

I think session_destroy() and session_unset() should be used at the same time to make sure that session data is surely deleted.

我认为应该同时使用 session_destroy() 和 session_unset() 以确保会话数据确实被删除。