Error Handling

[Sleeper]

I have set an SQL field as unique so that duplicates can't be entered, however rather then having the page error out and show the Error: Duplicate entry 'entry' for key 'field' I would like to be able to have a little div appear and say something like "this entry already exists" I already have it set to show that the item has been added but I have no idea were to start to make this work.

 

Any ideas?

 

Thanks,

Jim

[Pikachu2000]

The error number for a duplicate entry should be 1062. You can use mysql_errno with a conditional to check for a duplicate entry error.

[Sleeper]

I know im a nube but can you explain that a bit more on how I would do that?

[BlueSkyIS]

alternatively, don't let the error happen. check to see if there is a duplicate and tell the user if there is one.

[Sleeper]

That would be exactly what I want to do, however I don't know how to go about doing that. That's the reason for this post.

[BlueSkyIS]

I would use a SQL select statement to check if there is already a record with the matching value. if the number of results returned == 0, then there is no existing match and everything is okay. if the number of results > 0, there is a match and the user should get the warning.

[Sleeper]

Again your telling me what I want to do, but not really giving me an answer of how to do that..lol.

[Pikachu2000]

That works also. I usually check for the error just to minimize the number of queries that get executed.

[BlueSkyIS]

Again your telling me what I want to do, but not really giving me an answer of how to do that..lol.

 

I assume that you know how to run a SQL query in PHP, as the question pertains to a problem you see when you do that. So which part do you have questions on, the PHP or the SQL syntax?

[Sleeper]

To keep things moving at a good speed I think it would be better to let it give the error rather then checking every field in the table. I know I can do INSERT IGNORE INTO and it will ignore the error and just do nothing. But then it will come back like its been inserted as far as the user would know. What I want to do is using some type of coding that will check to see if there is an error when inserting and then if there is to display the text saying the option already exists. Is that possible and if so how?

 

Of that is not possible, what code would I use to have it check the existing fields to see if a duplicate exists?

[BlueSkyIS]

To check to see if there was an error:

The error number for a duplicate entry should be 1062. You can use mysql_errno with a conditional to check for a duplicate entry error.

 

To check existing fields:

I would use a SQL select statement to check if there is already a record with the matching value. if the number of results returned == 0, then there is no existing match and everything is okay. if the number of results > 0, there is a match and the user should get the warning.

 

example:

 

$inputval = 'something';

// Does this value exist in field somefield in table sometable?
$sql = "SELECT id FROM sometable WHERE somefield = '".mysql_real_escape_string($inputval)."'";
$result = mysql_query($sql) or die(mysql_error());
if (mysql_numrows($result) > 0) {
     // This value already exists, so show error
} else {
     // This value does not already exist
}

[Sleeper]

Ok I put that into effect but I'm still getting the error rather then the wanted effect. Here is the code I have maybe I'm missing something.

 

if ($add == yes){

$sql = "SELECT id FROM $GT WHERE link = '".mysql_real_escape_string(htmlentities($_POST[link]))."'";
$result = mysql_query($sql) or die(mysql_error());
if (mysql_numrows($result) > 0)
{
echo "<div id='success'><table border='0' cellpadding='0' cellspacing='0' width='450' class='success'><tr>
<td valign='top' align='center'>ERROR: This Link Already Exists!</td></tr></table></div>
<script type='text/javascript'>
window.setTimeout('closeHelpDiv();', 5000);
function closeHelpDiv(){ document.getElementById('success').style.display='none';}</script>";
}else {
$data="INSERT INTO $GT (link)
VALUES ('".mysql_real_escape_string(htmlentities($_POST[link]))."')";
if (!mysql_query($data,$con))
    die('Error: ' . mysql_error());
echo "<div id='success'><table border='0' cellpadding='0' cellspacing='0' width='450' class='success'><tr>
<td valign='top' align='center'>New Link Added Successfully!</td></tr></table></div>
<script type='text/javascript'>
window.setTimeout('closeHelpDiv();', 5000);
function closeHelpDiv(){ document.getElementById('success').style.display='none';}</script>";
}}

[BlueSkyIS]

die('Error: ' . mysql_error());

 

this causes the code to stop and display mysql_error(). you should remove that line and get mysql_errno() to check for error number 1062, which is duplicate key

[Sleeper]

that worked. Ty.