Member Avatar for trtcom1

Hi,
I need somebody to have a look at my code below and help to see what I have done wrong.
I have 3 tables:Student (studentNum,firstName,lastName), course (courseID,courseTotalCapacity), course_allocation (studentNum,courseID).
The AIM is to allocate students to 2 classes (courses 101 and 102) as long as there is available space in the class,if a class is full an error message is shown.
As it is the code adds student to a class even after reaching the courseTotalCapacity.
And sometimes I am also getting duplicate errors.
The else part of the code appears as TRUE whether the class is empty or full.
Please advise!

<html>
<body>

<form action="<?php echo $_SERVER['PHP_SELF'];?>" method="post">
<table>
<tr><td>Student ID:</td><td><input type="text" name="studentNum"/></td></tr>

<tr><td>FirstName:</td><td><input type="text" name="firtName"/></td></tr>
<tr><td>LastName:</td><td><input type="text" name="lastName"/></td></tr>


<tr><td>Course ID:</td><td><input type="text" name="courseID"/></td></tr>

<tr><td colspan="2" align="centre"><input type="submit" value="SUBMIT"/></td></tr>
</table>
</form>
<?php

// Connect to the database server
 $dbcnx = @mysql_connect('localhost', 'root', 'geco');
 if (!$dbcnx) {
   exit('<p>Could not connect to the ' .
       'database server.</p>');
 }//end of if-statement

 // Select the trainee_allocation database
 if (!@mysql_select_db('trainee_allocation')) {
   exit('<p>Cannot locate the trainee_allocation ' .
       'database.</p>');
 }//end of if-statement


//Traverse through the COURSE_ALLOCATION table and count the number of entries for
//each user id, aka: how many students per course.

$result = mysql_query('SELECT courseID, courseTotalCapacity FROM course WHERE courseID IN (101, 102)') or exit(mysql_error());
while ($row = mysql_fetch_assoc($result)) 
{
	$course_array[$row['courseID']]['courseTotalCapacity'] = $row['courseTotalCapacity'];
}//end of while-loop

$result = mysql_query('SELECT courseID, COUNT(*) AS count FROM course_allocation WHERE courseID IN (101, 102) GROUP BY courseID') or exit(mysql_error());
while ($row = mysql_fetch_assoc($result)) 
{
	$course_array[$row['courseID']]['count'] = $row['count'];
}//end of while-loop

echo "<br />";

   $studentNum = $_POST['studentNum'];
   $firtName = $_POST['firtName'];
   $lastName = $_POST['lastName'];

   $courseID = $_POST['courseID'];

  foreach ($course_array as $key => $value)
  {
      if ($value['count'] < $value['courseTotalCapacity'])
      { 
   	    $sql = "INSERT INTO student SET
       		studentNum='$studentNum',
		firtName='$firtName',
        	lastName='$lastName'";


		if (@mysql_query($sql)) {
		     echo '<p>Submitted student has been added.</p>';
		} else {
		     echo '<p>Error adding submitted student: ' .
		         mysql_error() . '</p>';
		}


	    $sql1 = "INSERT INTO course_allocation SET
		studentNum='$studentNum',
	
		courseID='$courseID'";

		if (@mysql_query($sql1)) {
		     echo '<p>Submitted student has been allocated.</p>';
		} else {
		     echo '<p>Error allocating submitted student: ' .
	         mysql_error() . '</p>';
		}
	}//end of if-statement
	else
	{
		echo 'sorry. you have reached the limit for course #' . $key;
		echo "<br />";
	}//end of else

  }//end of foreach-loop 

   
?>
</body>
</html>
  • 2 Contributors
  • 3 Replies
  • 166 Views
  • 2 Days Discussion Span
  • Latest Post Latest Post by trtcom1
Member Avatar for somedude3488

run a print_r on the course_array variable. make sure its being formatted correctly.

Member Avatar for trtcom1

When I run

print_r($course_array);

inside both while-loops and I get the results below but I cannot see what is wrong with it.Any help? Any more advices?

Array
(
    [101] => Array
        (
            [courseTotalCapacity] => 10
        )

)

Array
(
    [101] => Array
        (
            [courseTotalCapacity] => 10
        )

    [102] => Array
        (
            [courseTotalCapacity] => 10
        )

)


Array
(
    [101] => Array
        (
            [courseTotalCapacity] => 10
            [count] => 9
        )

    [102] => Array
        (
            [courseTotalCapacity] => 10
        )

)


Array
(
    [101] => Array
        (
            [courseTotalCapacity] => 10
            [count] => 9
        )

    [102] => Array
        (
            [courseTotalCapacity] => 10
            [count] => 9
        )

)
Member Avatar for trtcom1

Replaced the following

foreach ($course_array as $key => $value)
{

}

with:

if ($course_array[$courseID]['count'] < $course_array[$courseID]['courseTotalCapacity'])
{ 
       INSERT_QUERY();
}
else
{
       SAY THE CLASS IS FULL
}

everything works fine now.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.