PHP - Proper message when deleting data which is not there in database

Asked By rana pranav on 24-Jun-13 09:04 AM

I have written basic HTML code and php as follows

<html>
<head>
<title>Delete a Record from MySQL Database</title>
</head>
<body>
<?php
if(isset($_POST['delete']))
{

$conn = mysql_connect("localhost", "root","");
$Roll_No = $_POST['Roll_No'];
mysql_select_db("d",$conn);

$sql='DELETE FROM student WHERE Roll_No = "' .$Roll_No. '"';

$retval = mysql_query($sql);

if($retval)
{
echo "data deleted successfully\n";
}
else
{
die('Could not delete data: ' . mysql_error());
}
mysql_close($conn);
}
else
{
?>
<form method="post" action="<?php $_PHP_SELF ?>">
<table width="400" border="0" cellspacing="1" cellpadding="2">
<tr>
<th width="150">Student Roll No</t>
<td><input name="Roll_No" type="text" id="Roll_No"></td>
</tr>
<tr>
<td width="100"> </td>
<td> </td>
</tr>
<tr>
<td width="100"> </td>
<td>
<input name="delete" type="submit" id="delete" value="Delete">
</td>
</tr>
</table>
</form>
<?php
}
?>
</body>
</html>

I have entered data as follows in student table (roll no, name respectively)

1 Sunil

2 Dhaval

When I run page and if I write either 1 or 2(data which is already there in table) then it deletes successfully with message deleted data successfully which is ok but

If I write 4 in textbox then it gives message as deleted data successfully even if there is no rollno :- 4 instead displaying could not delete data with error

focus mistake and rewrite code here…