Hi,
I am new to php and need help.
I am building a library system for an assignment.
I want to provide a functionality that registers (adds) all transactions to defferent databases.
I am stuck on how to add a selected row (selected by a checkbox) to the database and make sure that 2 users cannot update the same record at the same time.
Thanks for your help.
bellow is my code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=windows-1250">
<meta name="generator" content="PSPad editor, www.pspad.com">
<title>Web Works DD - Web Development & Software Solutions</title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script>
<link rel="stylesheet" type="text/css" href="css/style.css" />
</head>
<body>
<!--<div class="utilities">
<!-- UTILITIES MENU --
<a href="index.php" style=text-decoration:none;><img src="images/home.png" border="0" alt="Home Page"/> Home Page</a> <a href="sitemap.php" style=text-decoration:none;><img src="images/sitemap.png" border="0" alt="Sitemap"/> Sitemap</a>
</div><!-- END UTILITIES -->
<div id="right_bar"> <!-- right bar starts here -->
</div> <!-- end of right bar -->
<div id="top_bar"> <!-- top bar starts here -->
<a href="index.php" style=text-ecoration:none; title="Web Works DD - Web Development & Software Solutions"><img src="images/mainLib.jpg" border=0 style=height:180;/> </a>
<img src="images/topText.jpg" border=0 style=height:180;/>
</div> <!-- end of top bar -->
<div id="container">
<div id="top-logo">
<!--<a href="index.php" style=text-ecoration:none; title="Web Works DD - Web Development & Software Solutions"><img src="images/Main_logo.jpg" border=0 /> </a> -->
</div>
<ul class="dropdown dav">
<li><a href="index1.php">HOME</a></li>
<li><a href="#" class="dir">VIEW RWSOURCES</a>
<ul>
<li><a href="books.php">BOOKS</a></li>
<li><a href="dvds.php">DVDS</a></li>
<li><a href="journals.php">JOURNALS</a></li>
</ul>
</li>
<li><a href="staffLogin.php">STAFF ZONE</a></li>
<li><a href="studentsLogin.php">STUDENT ZONE</a></li>
</ul>
<table>
<!--This defines a new form -->
<form action="" method="post">
<!--This creates the dropdown in html-->
<select name="fields">
<option value="1">Please select...</option>
<option value="isbnno">isbnno</option>
<option value="title">title</option>
<option value="description">description</option>
<option value="author">author</option>
</select>
</td>
</tr>
<tr>
<td>
<input type="text" name="value" size="40">
</td>
</tr>
<tr>
<td>
<!-- Create a button -->
<input type="submit" value="Select" name="select">
</td>
</tr>
</form>
</table>
<?php
session_start();
include("secure/db_open.php");
/* $myusername=$_SESSION['myusername'];
echo $myusername;
$insert = $checkbox[$i];
$cops = $_POST['copies'];
$userid ="SELECT id FROM students WHERE username = '$myusername'";
$uido = mysql_query($userid);
$row = mysql_fetch_array($uido);
echo $row['id']; */
// get variable after selecting something from the dropdown with name 'fields'
$select = $_POST['select'];
$valu = $_POST['value'];
// if something has been chosen
if (!empty($select))
{
$fields = $_POST['fields']; //get the chosen value
$allbooks="SELECT * FROM books WHERE {$fields} = '$valu'";
//select books that are available - driven by the user's input
$copas="SELECT * FROM books WHERE {$fields} = '$valu' AND available_copies > 0";
$copy = mysql_query($copas);
//count the number of rows resulting from the query
$count=mysql_num_rows($copy);
//$copse = mysql_fetch_array($copy);
//select books that are not available
$notavailable="SELECT * FROM books WHERE {$fields} = '$valu' AND available_copies = 0";
$shownotavailable=mysql_query($notavailable);
$count1=mysql_num_rows($shownotavailable);
//display a form
echo "<table width='1100' border='0' cellspacing='1' cellpadding='0'>";
echo "<tr>";
echo "<td>" ;
echo "<form name='form1' method='post' action=''>";
echo "<table width='1100' border='0' cellpadding='3' cellspacing='1' bgcolor='#CCCCCC'>";
echo "<tr>";
echo "<td align='center' colspan='9' bgcolor='#FFFFFF'>";
echo "<strong>Available to Loan </strong>" ;
echo "</td>";
echo "</tr>";
echo "<tr>";
echo "<td align='center' bgcolor='#FFFFFF'>Loan</td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>ISBN No.</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Title</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Description</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Author</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Loan Type</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Location</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Available Copies</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Desired Num of Copies</strong></td>";
echo "</tr>";
while(($row = mysql_fetch_assoc($copy)))
{
echo "<tr>";
echo "<td align='center' bgcolor='#FFFFFF'><input name='checkbox[]' type='checkbox' id='checkbox[]' value=".$row['bookid']."></td>";
echo "<td>" .$row['isbnno']. "</td>";
echo "<td>" .$row['title']. "</td>";
echo "<td>" .$row['description']. "</td>";
echo "<td>" .$row['author']. "</td>";
echo "<td>" .$row['loan_type']. "</td>";
echo "<td>" .$row['location']. "</td>";
echo "<td>" .$row['available_copies']. "</td>";
echo "<td align='center' bgcolor='#FFFFFF'><input name='copies' type='text' id='copies' size='2'></td>";
echo "</tr>";
}
echo "<tr>";
echo "<td colspan='9' align='center' bgcolor='#FFFFFF'><input name='loan' type='submit' id='loan' value='Loan Book'></td>";
echo "</tr>";
echo "</table>";
if (isset($_POST))
{
session_start();
$myusername=$_SESSION['myusername'];
$cops = $_POST['copies'];
$userid ="SELECT id FROM students WHERE username = $myusername";
$uido = mysql_query($userid);
$row1 = mysql_fetch_array($uido);
$sid = $row1['id'];
for ($i=0;$i<$count;$i++)
{
$insert = $checkbox[$i];
//echo "Welcome, ".$row['id'];
$insertloaned="INSERT INTO studentloanedbooks(studentid, bookid, noofcopies) VALUES ($sid, $insert, $cops)";
$loaned = mysql_query($insertloaned);
}
}
if($count1>0)
{
//display the books details
//display a form
echo "<br>";
echo "<br>";
echo "<table width='1100' border='0' cellspacing='1' cellpadding='0'>";
echo "<tr>";
echo "<td>" ;
echo "<form name='form1' method='post' action=''>";
echo "<table width='1100' border='0' cellpadding='3' cellspacing='1' bgcolor='#CCCCCC'>";
echo "<tr>";
echo "<td align='center' colspan='9' bgcolor='#FFFFFF'>";
echo "<strong>Available to Loan </strong>" ;
echo "</td>";
echo "</tr>";
echo "<tr>";
echo "<td align='center' bgcolor='#FFFFFF'>Loan</td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>ISBN No.</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Title</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Description</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Author</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Loan Type</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Location</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Available Copies</strong></td>";
echo "<td align='center' bgcolor='#FFFFFF'><strong>Desired Num of Copies</strong></td>";
echo "</tr>";
while(($row = mysql_fetch_assoc($shownotavailable)))
{
echo "<tr>";
echo "<td align='center' bgcolor='#FFFFFF'><input name='checkbox[]' type='checkbox' id='checkbox[]' value='.$row[bookid]'></td>";
echo "<td>" .$row['isbnno']. "</td>";
echo "<td>" .$row['title']. "</td>";
echo "<td>" .$row['description']. "</td>";
echo "<td>" .$row['author']. "</td>";
echo "<td>" .$row['loan_type']. "</td>";
echo "<td>" .$row['location']. "</td>";
echo "<td>" .$row['available_copies']. "</td>";
echo "<td align='center' bgcolor='#FFFFFF'><input name='copies' type='text' id='copies' size='2'></td>";
echo "</tr>";
}
echo "<tr>";
echo "<td colspan='9' align='center' bgcolor='#FFFFFF'><input name='reserve' type='submit' id='reserve' value='Reserve Book'></td>";
echo "</tr>";
echo "</table>";
}
}
// include("secure/db_close.php");
//include("secure/db_close.php");
?>
<!--if($cop>0){ -->
<!-- this is my footer div -->
<div id="footer">
Copyright © 2010 | <a href="privacy.php">Privacy Policy</a> | <a href="terms.php">Terms of Service</a>
<img src="images/mini_logo1.png" align="right" style="margin-right:5" />
</div> <!-- End footer div -->
</div>
</div>
</body>
</html>
MOD EDIT:
. . .
BBCode tags added.
