Jules Geernaert Jules Geernaert - 7 months ago 34
SQL Question

How to check if a checkbox returns a value? Error:"Notice: Undefined index:"

I am working on my final project in my final grade.
I'm currently working on a site linked with mysql for a dance school.
I want to check if a checkbox returns a value or not.
It gives a "undefined index"-error at the "if($_POST['dansstijl'.$i.''])" and I don't know what i'm doing wrong.

Sorry if there are parts in dutch!

Here's a big part of the code:

$sql1="INSERT INTO tblinschrijvingen(llnID) VALUES('".$lln_id."')";
if(!$result1=$mysqli-> query($sql1))
{trigger_error('Fout bij query: '.$mysqli->error);}
else

{
$sql2="SELECT inschrijvingsID FROM tblinschrijvingen ORDER BY inschrijvingsID DESC LIMIT 1";
if(!$result2=$mysqli-> query($sql2))
{trigger_error('Fout bij query: '.$mysqli->error);}
else
{
for($i=1;$i<=11;$i++)
{
if($_POST['dansstijl'.$i.''])
{
$row=$result2->fetch_assoc();
$inschrijvingsID=$row['inschrijvingsID'];

$sql3="SELECT DansID, vestiging, Dansstijl FROM tbldanslessen WHERE vestiging='".$vestiging."' AND Dansstijl='".$_POST['dansstijl'.$i.'']."'";

echo($sql3);
if(!$result3=$mysqli-> query($sql3))
{trigger_error('Fout bij query: '.$mysqli->error);}
else
{
$row=$result3->fetch_assoc();
$dansID=$row['DansID'];

$sql4="INSERT INTO tblinschrijvingenperdansles(inschrijvingsID, dansID) VALUES ('".$inschrijvingsID."', '".$dansID."')";
if(!$result4=$mysqli-> query($sql4))
{trigger_error('Fout bij query: '.$mysqli->error);}
else
{
}
}
}
}
}


Here are my checkboxes:

<table border="0">
<tbody>
<tr>
<td width="199"><label>
<input type="checkbox" name="dansstijl1" value="Peuterballet" id="dansstijl1">
Peuterballet</label></td>
<td width="162"><label>
<input type="checkbox" name="dansstijl2" value="Preballet" id="dansstijl2">
Preballet</label></td>
</tr>
<tr>
<td><label>
<input type="checkbox" name="dansstijl3" value="Preprimary" id="dansstijl3">
Preprimary</label></td>
<td><label>
<input type="checkbox" name="dansstijl4" value="Primary" id="dansstijl4">
Primary</label></td>
</tr>
<tr>
<td><label>
<input type="checkbox" name="dansstijl5" value="Klassiek" id="dansstijl5">
Klassiek</label></td>
<td><label>
<input type="checkbox" name="dansstijl6" value="Modern Jazz" id="dansstijl6">
Modern Jazz</label></td>
</tr>
<tr>
<td><label>
<input type="checkbox" name="dansstijl7" value="Hedendaags" id="dansstijl7">
Hedendaags</label></td>
<td><label>
<input type="checkbox" name="dansstijl8" value="Musical" id="dansstijl8">
Musical</label></td>
</tr>
<tr>
<td><label>
<input type="checkbox" name="dansstijl9" value="Pointes" id="dansstijl9">
Pointes</label></td>
<td>&nbsp;</td>
</tr>
<tr>
<td><label>
<input type="checkbox" name="dansstijl10" value="Hiphop - Breakdance" id="dansstijl10">
Hiphop - Breakdance</label></td>
<td><label>
<input type="checkbox" name="dansstijl11" value="Hiphow - Crew" id="dansstijl11">
Hiphow - Crew</label></td>
</tr>
</tbody>
</table>


Thank you on forehand!

Jules

Answer

Change

if($_POST['dansstijl'.$i.''])

to

if (isset($_POST['dansstijl'.$i.'']))

This checks whether or not the dansstijl is set, instead of trying to get the value of the dansstijl(which may not exist,thus giving you the error).