Link from a table entry

rich_northumbria · April 25, 2010

Hello

I am very new to PHP and doing some work for Uni. I was hoping for a little bit of guidance.

I am creating a website however here is a snippet as I test.

http://www.numyspace.co.uk/~unn_s007753/catList.php

When the user selects a category I am hoping to link the book title to the review page however I am unsure how to do this. ie wot sort of query to use.

Help but be greatly appreciated

Regards

Rich

Pikachu2000 · April 25, 2010

The link should be along the lines of echo "<a href=\"http://site.com/book_detail.php?id=$db_row['id']\">$db_row['title']</a>";

Then the query to retrieve the review uses the $GET['id'] parameter.

$id = (int) $_GET['id']

SELECT whatever_columns FROM whatever_table WHERE id = $id

Hope that makes sense.

rich_northumbria · April 25, 2010

Attached is the code which I have currently.

Could you please explain using my code if possible as I seem to have errors

Can I ask a couple of questions on it please?

Some of the books within the drop down box are duplicated, how do I remove the duplication?

When you have selected a book how do I make the drop down box with the ISBN invisible but stay in the address bar?

http://www.numyspace.co.uk/~unn_s007753/testpage.php

Cheers

Rich

[attachment deleted by admin]

Pikachu2000 · April 25, 2010

You need to make sure your file.php?value=whatever in the url matches the value you're trying to retrieve with $_REQUEST. For example, in the displaybooklist1.php file, you look for the value of $_REQUEST['bookISBN'] coming from displaycatlist.php, but you're passing the value as '?name='. That causes the undefined index error, and the subsequent failure of the script to function as it should.

rich_northumbria · April 25, 2010

Thanks for your quick replies.

How would this be changed?

Ie which lines and pages need altering.

Does this mean my coding in the link is correct as long as i match the variables correctly?

Pikachu2000 · April 25, 2010

From what I was able to see, the problems you're having are all related to the mismatches in the names of the variables. You need to change the <a href= url string in the displaycatlist.php script so the variable name is correct. ( ?bookISBN= rather than ?name= ) The best thing to do is test your pages, and pay attention to the error messages. Those should give you the information you need to track all of these down and correct them.

rich_northumbria · April 25, 2010

The error is coming for this page:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<head>

<title>Northumbria Book Club</title>

</head>

<body>

<?php

//Connect to datebase

require_once('dbconnect.php');

//get the book from the request

$bookTitle = $_REQUEST['bookISBN'];

//Create SQL statement to retrieve the book

$booksSQL = "SELECT nbc_book.bookISBN, nbc_book.catID, nbc_book.bookYear, nbc_book.bookTitle, nbc_book.bookPrice, nbc_authbook.authorID, nbc_author.authorName

FROM nbc_book

LEFT JOIN nbc_authbook

ON nbc_book.bookISBN = nbc_authbook.bookISBN

LEFT JOIN nbc_author

ON nbc_authbook.authorID = nbc_author.authorID

LEFT JOIN nbc_bookreview

ON nbc_book.bookISBN = nbc_bookreview.bookISBN

where nbc_book.bookISBN = '$bookTitle';";

$rsbookDetails = mysql_query($booksSQL);

echo "<h1>Northumbria Book Club</h1>";

echo "<table border=\"1\">";

echo "<tr><th>Book ISBN</th><th>Book Title</th><th>Book Year</th><th>Author</th><th>Category</th><th>Price</th></tr>";

while($list = mysql_fetch_array($rsbookDetails)){

$bookISBN = $list['bookISBN'];

$bookTitle = $list['bookTitle'];

$bookYear = $list['bookYear'];

$authorName = $list['authorName'];

$catID = $list['catID'];

$bookPrice = $list['bookPrice'];

echo "<tr><td>$bookISBN</td><td>$bookTitle</td><td>$bookYear</td><td>$authorName</td><td>$catID</td><td>$bookPrice</td></tr>";}

echo "</table>";

//Create SQL statement to retrieve the book

$userSQL = "select userID, userName FROM nbc_user ORDER BY userName";

$rsUserList = mysql_query( $userSQL );

echo "<select name=\"userID\">";

while($Ulist = mysql_fetch_array( $rsUserList )){

$userID = $Ulist['userID'];

$userName = $Ulist['userName'];

echo "<option value=\"$userID\">$userName</option>";}

echo "</select>";

$user1SQL = "SELECT nbc_book.bookISBN

FROM nbc_book";

$rsUserList1 = mysql_query( $user1SQL );

echo "<select name=\"bookISBN\">";

{

$userID = $Ulist1['bookISBN'];

echo "<option value=\"$bookISBN\">$bookISBN</option>";

}

echo "</select>";

?>

</br>

<p>Upon selecting a book to review, please pick a user from the dropdown list above. Within the box probived state your views and opinions on the book and click “Submit Review”.</p>

<p><strong>Please note:</strong> It is more beneficial for other readers to have an appropiate review rather than a couple of words which does not describe the book.</p>

<p>Kind Regards</p>

<p>Northumbria Book Club</p>

<?php

$bookTitle = $_REQUEST['bookISBN'];

$reviewSQL = "SELECT nbc_bookreview.bookISBN, nbc_bookreview.userID, nbc_bookreview.reviewDate, nbc_bookreview.reviewText

FROM nbc_book

LEFT JOIN nbc_bookreview

ON nbc_book.bookISBN = nbc_bookreview.bookISBN

where nbc_book.bookISBN = '$bookTitle';";

$rsreviw = mysql_query($reviewSQL);

echo "<h1>User Reviews</h1>";

echo "<table border=\"1\">";

echo "<tr><th>Book ISBN</th><th>User ID</th><th>Review Date</th><th>Review Text</th></tr>";

while($list = mysql_fetch_array($rsreviw)){

$bookISBN = $list['bookISBN'];

$userID = $list['userID'];

$reviewDate = $list['reviewDate'];

$reviewText= $list['reviewText'];

echo "<tr><td>$bookISBN</td><td>$userID</td><td>$reviewDate</td><td>$reviewText</td></tr>";}

echo "</table>";

?>

</form>

</body>

</html>

I believe its due to having $bookTitle = $_REQUEST['bookISBN']; twice on the page however it causes further errors if i remove it.

Any advice

cheers

Pikachu2000 · April 25, 2010

Paste in the error it's spitting out . . .

rich_northumbria · April 25, 2010

Notice: Undefined index: bookISBN in /var/www/vhosts/numyspace.co.uk/web_users/home/~unn_s007753/public_html/displaybooklist1.php on line 13

Notice: Undefined index: bookISBN in /var/www/vhosts/numyspace.co.uk/web_users/home/~unn_s007753/public_html/displaybooklist1.php on line 94

Both these lines contain $bookTitle = $_REQUEST['bookISBN'];

Pikachu2000 · April 25, 2010

OK. That all goes back to what I was saying earlier. The file that is sending the value to the displaybooklist.php script is not send the variable with the correct name. Here's an (oversimplified) example of what I mean:

form.php

<?php
// this sends a variable via the url to process.php. Note that I've misspelled 'number' in the url string
$number = 123456;
echo "<a href=\"process.php?numer=" . $number . "\">Send value</a>";
?>

process.php

<?php
$number = $_GET['number'];
echo $number;
?>

This will show an "undefined index" error on line 1 of process.php, even though the actual error is in form.php. That is what is happening to you. You're sending the proper value to the second script, but with the wrong name and it's triggering the undefined index errors, and not setting the variable values correctly. Does that help?

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