Accessing a POST variable in another PHP File [duplicate] - php

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Closed 10 years ago.
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Simplest method of passing one php variable in a url
I am making a quiz application. At the faculty end, teachers get to type the topic name (with which I will form a vanity URL), and type 3 questions with possible options including answer in one of them. Everytime a teacher creates a quiz, a new table will be created with the questions, options and answers everytime.
My db.php file:
<?php
mysql_connect("localhost","root","");
mysql_select_db("quiz");
?>
My faculty.php file:
<form action="fac_handler.php" method="POST">
Quiz Topic:<br><input type="text" name="topic"><br><br>Enter Questions:<br><br>
<?php
$a="a";
$b="b";
$c="c";
$d="d";
for ($i=1; $i<=3;$i++)
{
?>
Question <?php echo $i?>:<br>
<textarea type="text" name="<?php echo "q".$i;?>"></textarea><br>
<br>
<input type="text" name="<?php echo $a.$i; ?>">
<input type="text" name="<?php echo $b.$i; ?>">
<input type="text" name="<?php echo $c.$i; ?>">
<input type="text" name="<?php echo $d.$i; ?>"> <br><hr>
<?php
}
?>
<br>
<input type="submit" value="Submit">
</form>
My fac_handler.php file:
<?php
require "db.php";
if(isset($_POST['topic']) && !empty($_POST['topic']))
{
$topic=$_POST['topic'];
if(isset($_POST['q1'])&&isset($_POST['a1'])&&isset($_POST['b1'])&&isset($_POST['c1'])&&isset($_POST['d1']))
{
if(!empty($_POST['q1']) && !empty($_POST['a1']) && !empty($_POST['b1']) && !empty($_POST['c1']) && !empty($_POST['d1']))
{
$q1=$_POST['q1'];
$a1a=$_POST['a1'];
$a1b=$_POST['b1'];
$a1c=$_POST['c1'];
$a1d=$_POST['d1'];
}
else
{
echo "Please Set the Questions and the Options!";
die();
}
}
if(isset($_POST['q2'])&&isset($_POST['a2'])&&isset($_POST['b2'])&&isset($_POST['c2'])&&isset($_POST['d2']))
{
if(!empty($_POST['q2']) && !empty($_POST['a2']) && !empty($_POST['b2']) && !empty($_POST['c2']) && !empty($_POST['d2']))
{
$q2=$_POST['q2'];
$a2a=$_POST['a2'];
$a2b=$_POST['b2'];
$a2c=$_POST['c2'];
$a2d=$_POST['d2'];
}
else
{
echo "Please Set the Questions and the Options!";
die();
}
}
if(isset($_POST['q3'])&&isset($_POST['a3'])&&isset($_POST['b3'])&&isset($_POST['c3'])&&isset($_POST['d3']))
{
if(!empty($_POST['q3']) && !empty($_POST['a3']) && !empty($_POST['b3']) && !empty($_POST['c3']) && !empty($_POST['d3']))
{
$q3=$_POST['q3'];
$a3a=$_POST['a3'];
$a3b=$_POST['b3'];
$a3c=$_POST['c3'];
$a3d=$_POST['d3'];
}
else
{
echo "Please Set the Questions and the Options!";
die();
}
}
$ans1=$a1a;
$ans2=$a2a;
$ans3=$a3a;
$qtbname="q_".$topic;
$top=$_SESSION['topic']=serialize($_POST['topic']);
$new="q_".$top;
$create_table="CREATE TABLE $qtbname(id int NOT NULL AUTO_INCREMENT,question VARCHAR(500),answer VARCHAR(30),optiona VARCHAR(30),optionb VARCHAR(30),optionc VARCHAR(30),optiond VARCHAR(30),PRIMARY KEY (id))";
mysql_query($create_table);
$query1="INSERT INTO $qtbname VALUES('','$q1','$ans1','$a1a','$a1b','$a1c','$a1d')";
$query2="INSERT INTO $qtbname VALUES('','$q2','$ans2','$a2a','$a2b','$a2c','$a2d')";
$query3="INSERT INTO $qtbname VALUES('','$q3','$ans3','$a3a','$a3b','$a3c','$a3d')";
$result1=mysql_query($query1);
$result2=mysql_query($query2);
$result3=mysql_query($query3);
header("Location: student.php");
}
else
{
echo "Please Set the Quiz Topic";
}
?>
Now as you can see, after the table gets created dynamically everytime with a table prefix, it gets redirected to student.php file which looks like this.
My student.php file:
<?php
require "db.php";
$query="SELECT * FROM $new";
$result=mysql_query($query);
$n="1";
$i="a";
while($row=mysql_fetch_assoc($result))
{
echo "Question ".$n." : ".$row['question'];
echo "<br>";
$ansr=$row['answer'];
?>
<form action="std_handler.php" method="POST">
<input type="radio" name="<?php echo $i; ?>" value="<?php echo $row['optiona']; ?>"><?php echo $row['optiona']; ?>
<input type="radio" name="<?php echo $i; ?>" value="<?php echo $row['optionb']; ?>"><?php echo $row['optionb']; ?>
<input type="radio" name="<?php echo $i; ?>" value="<?php echo $row['optionc']; ?>"><?php echo $row['optionc']; ?>
<input type="radio" name="<?php echo $i; ?>" value="<?php echo $row['optiond']; ?>"><?php echo $row['optiond']; ?><br>
<?php
++$i;
++$n;
}
?>
<input type="submit" value="Submit">
</form>
The fourth line in this student.php file, the query, $query="SELECT * FROM $new";, I need to access the table which I just created at the faculty end to display the questions and answers in text and radio button format.
Here is my std_handler.php file:
<?php
if(isset($_POST['a']))
{
$ans=$_POST['a'];
echo $ans;
echo "<br>";
}
if(isset($_POST['b']))
{
$ans=$_POST['b'];
echo $ans;
echo "<br>";
}
if(isset($_POST['c']))
{
$ans=$_POST['c'];
echo $ans;
echo "<br>";
}
?>
In the faculty handler file, after the validations, I tried to use session and get the variable, I tried to make it global, I tried serializing it, I couldn't succeed to use and select the dynamic table name in the student.php page.
What I want is, as soon as I get redirected to the student.php page, I want to select the table instantly created earlier, how do I do that? How do I access that variable with which I created the table and executed the query at the faculty end?
I keep getting this error: Notice: Undefined variable: new in C:\xampp\htdocs\quiz\student.php on line 4
Please help me solve this problem. Thank you.

Answer 1

Do you want something like this:
Bad solution, but you can see how to pass a variable
In fac_handler.php:
Change
header("Location: student.php");
to
header("Location: student.php?url=". urlencode($new));
On the student page:
$query="SELECT * FROM " . mysql_real_escape_string($_GET["url"]);
This is a method, but if I where you I would do this on an other way.
How I would do this
Create a ID that you send and resolve that name to the ride database name.

Answer 2

If I had to guess I would say this. When it gives you this error: Notice: Undefined variable: new in C:\xampp\htdocs\quiz\student.php on line 4 it's because it's just that. If we look at the code here:
require "db.php";
$query="SELECT * FROM $new";
$result=mysql_query($query);
$n="1";
$i="a";
this is your student.php ^^^
You are not setting the value of $new.
So you need to actually define the value.
$new = $_GET['x'];
$query="SELECT * FROM $new";
$result=mysql_query($query);
$n="1";
$i="a";
Where x is whatever you are passing as your query value.
or something along those lines.

Answer 3

Okay, I solved this problem, this is what I did.
I removed these two from the fac_handler.php page:
$top=$_SESSION['topic']=serialize($_POST['topic']);
$new="q_".$top;
And few lined below, I changed the header location to:
header("Location: student.php?url=".$qtbname);
And in the student.php page, I changed my query to:
$query="SELECT * FROM " . mysql_real_escape_string($_GET["url"]);
For the last two modifications above, I sincerely thank Lawrence. Also Thunda thanks a lot for giving me that idea to use the GET variable thing too.
deceze and tim.baker (there in the comments): Thanks a lot for your advice too, now that I solved my problem, I will go ahead with normalization as you suggested.
Thanks a lot stackoverflow, was struggling with this for a long time.