duplicate checking of date and time using php
<p>I have a php web site, and here I need to create a page to enter exam details of a student. There are 5 Subject in one exam. Each subject has exam date, starting time and end time </p>

<p>I.e. </p>

<pre><code>Date: 02-nov-2012 
Start time: 2.30 pm
End time: 4.30 pm 
</code></pre>

<p>I have to check the duplication of the exam date time....i.e. any other subjects which don't have the similar date time also if one subject has </p>

<pre><code>Exam Date:  02-nov-2012 
Start time: 3.00.pm 
End date: 5.00 pm 
</code></pre>

<p>Must be avoided. It’s invalid 
Another subject has</p>

<pre><code>Exam Date:  02-nov-2012 
Start time: 9.00.am 
End date: 2.00 pm 
</code></pre>

<p>It’s a valid  </p>

<p>I think it's clear... I don't know to explain further in details....
I don't know to validate this in php </p>
