PHP函数-无法取消设置$ _SESSION变量

Question

I cannot unset a session variable for a PHP Function,

From the code below, If I enter a review into a site, with the $_SESSION['KEYWORD'] data it will post the correct data, but if I want to leave another review through a different $_SESSION variable, once it is added into MySQL it displays the value of the first review I entered $_SESSION['KEYWORD'] in this example...

    <?php session_start(); ?>
<?php include('db_connect.inc');?>
<link rel="stylesheet" type="text/css" href="style.css" />  



<?php 
if (isset($_SESSION['SUBURB'])) {
    $VAR = $_SESSION['SUBURB'];
    Set_Review($VAR);
    unset($VAR);

} elseif (isset($_SESSION['KEYWORD'])) {
        $VAR = $_SESSION['KEYWORD'];
        Set_Review($VAR);
        unset($VAR);

} elseif (isset($_SESSION['LOCATION'])) {
        $VAR = $_SESSION['LOCATION'];
        Set_Review($VAR);
        unset($VAR);

} elseif (isset($_SESSION['RATING'])) {
        $VAR = $_SESSION['RATING'];
        Set_Review($VAR);
        unset($VAR);

}
?>


<?php
function Set_Review($VAR) {
    include('db_connect.inc');
    $result = $conn->prepare("INSERT INTO dog_parks.reviews (review_text, username, date, rating, item) VALUES (:review, :id, :date, :rating, :park_value)");
    $result->bindParam(':review', $value1);
    $result->bindParam(':id', $value2);
    $result->bindParam(':date', $value3);
    $result->bindParam(':rating', $value4);
    $result->bindParam(':park_value', $value5);

    $value1 = $_POST['review'];
    $value2 = $_SESSION['id'];
    $value3 = $date = date("Y-m-d");
    $value4 = $_POST['rating'];
    $value5 = trim($VAR,    "'\"");
    $result->execute();
    echo "<h3>Review entry Successful, you will now be redirected to the home page</h3>";
    header( "refresh:5; url=index.php" );
    unset($VAR);
}
?>

Answer 1

Pass by reference: function Set_Review(&$VAR) . Use "&" before $VAR.

http://php.net/manual/en/language.references.pass.php

You will pass the memory address of $_SESSION variable, and then you can unset($VAR) the way you want.

Answer 2

You are unsetting the $VAR variable, not your $_SESSION variable. Try:

unset($_SESSION['KEYWORD'];

Answer 3

I think unset() ing the $_SESSION array is a bad way to do it. Just call session_destroy()

http://php.net/manual/it/function.session-destroy.php

If you want to delete only a part of the session data, try to enclose all those data in an array:

$_SESSION["deleteme"] = array();

$_SESSION["deleteme"]["val1"] = "someval";

Then:

unset($_SESSION["deleteme"]);

Answer 4

I have solved the issue..

Under each statement I added unset($_SESSION['session name here']);

    <?php 
if (isset($_SESSION['SUBURB'])) {
    $VAR = $_SESSION['SUBURB'];
    Set_Review($VAR);
    unset($_SESSION['SUBURB']);

} elseif (isset($_SESSION['KEYWORD'])) {
        $VAR = $_SESSION['KEYWORD'];
        Set_Review($VAR);
        unset($_SESSION['KEYWORD']);

} elseif (isset($_SESSION['LOCATION'])) {
        $VAR = $_SESSION['LOCATION'];
        Set_Review($VAR);
        unset($_SESSION['LOCATION']);

} elseif (isset($_SESSION['RATING'])) {
        $VAR = $_SESSION['RATING'];
        Set_Review($VAR);
        unset($_SESSION['RATING']);

}
?>