使用for循环向mysql输入数据

i have a dynamically generated form. the form generates itself when addmore button is clicked. this is my html form markup

  <form name="addcourses" action="" method="post">
<fieldset><legend>Add Courses</legend>
<table width="500px" border="0" id="tbltest">
  <tr>
    <td><select name="txtcategory0" id="id_str">
    <option value="" selected="selected"></option>
<option value="Management">Management</option>
<option value="Medical">Medical</option>
<option value="Dental">Dental</option>
<option value="Nursing">Nursing</option>
<option value="Ayurvedic">Ayurvedic</option>
<option value="Homeopathy">Homeopathy</option>
<option value="Unani">Unani</option>
<option value="Physiotherapy">Physiotherapy</option>
<option value="Pharmacology">Pharmacology</option>
<option value="Naturopathy & Yoga">Naturopathy & Yoga</option>
<option value="Engineering">Engineering</option>
<option value="Information Technology">Information Technology</option>
<option value="Computer / IT Training Institutes">Computer / IT Training Institutes</option>
<option value="Animation">Animation</option>
<option value="Polytechnic">Polytechnic</option>
<option value="Maritime">Maritime</option>
<option value="ITI">ITI</option>
<option value="Biotechnology">Biotechnology</option>
<option value="Law">Law</option>
<option value="Fashion Technology">Fashion Technology</option>
<option value="Hotel Management">Hotel Management</option>
<option value="Mass Media">Mass Media</option>
<option value="Distance Learning">Distance Learning</option>
<option value="Library Science">Library Science</option>
<option value="Degree Colleges">Degree Colleges</option>
<option value="B.Ed">B.Ed</option>
<option value="Fine Arts">Fine Arts</option>
<option value="Film Institutes">Film Institutes</option>
<option value="Tutorials">Tutorials</option>
<option value="Entrance Coaching">Entrance Coaching</option>
<option value="Vocational Courses">Vocational Courses</option>
<option value="Beautician Courses">Beautician Courses</option>
<option value="Language Courses">Language Courses</option>
<option value="Certificate Courses">Certificate Courses</option>
<option value="Schools">Schools</option>
<option value="International Schools">International Schools</option>
<option value="Private Schools">Private Schools</option>
<option value="Nursery / Play Homes">Nursery / Play Homes</option>
<option value="Flying Institutes">Flying Institutes</option>
<option value="Call Center Training">Call Center Training</option>
<option value="Sports Academy">Sports Academy</option>
<option value="10 + 2">10 + 2</option>
</select></td>
    <td><input type="text" name="txtcourse_name0" id="id_cname" value="" /></td>
    <td><input type="text" name="txtseat0" id="id_seats" value="" style="width:40px;" /></td>
    <td><select name="txtfees0" id="id_elig" >
<option value="" selected="selected"></option>
<option value="1 - 5000">1 - 5000</option>
<option value="5001 - 10000">5001 - 10000</option>
<option value="10001 - 20000">10001 - 20000</option>
<option value="20001 - 30000">20001 - 30000</option>
<option value=">30001 - 40000">30001 - 40000</option>
<option value="40001 - 50000">40001 - 50000</option>
<option value="50001 - 60000">50001 - 60000</option>
<option value="60001 - 70000">60001 - 70000</option>
<option value="70001 - 80000">70001 - 80000</option>
<option value="80001 - 90000">80001 - 90000</option>
<option value="90001 - 1 Lac">90001 - 1 Lac</option>
<option value="1 Lac - 1.5 Lac">1 Lac - 1.5 Lac</option>
<option value="1.5 Lac - 2 Lac">1.5 Lac - 2 Lac</option>
<option value="2.5 Lac - 3 Lac">2.5 Lac - 3 Lac</option>
<option value="3.5 Lac - 4 Lac">3.5 Lac - 4 Lac</option>
<option value="4.5 Lac - 5 Lac">4.5 Lac - 5 Lac</option>
<option value="5.5 Lac - 6 Lac">5.5 Lac - 6 Lac</option>
<option value="6.5 Lac - 7 Lac">6.5 Lac - 7 Lac</option>
<option value="7.5 Lac - 8 Lac">7.5 Lac - 8 Lac</option>
<option value="8.5 Lac - 9 Lac">8.5 Lac - 9 Lac</option>
<option value="9.5 Lac - 10 Lac">9.5 Lac - 10 Lac</option>
<option value="10.5 Lac - 11 Lac">10.5 Lac - 11 Lac</option>
<option value="11.5 Lac - 12 Lac">11.5 Lac - 12 Lac</option>
<option value="12.5 Lac - 13 Lac">12.5 Lac - 13 Lac</option>
<option value="13.5 Lac - 14 Lac">13.5 Lac - 14 Lac</option>
<option value="14.5 Lac - 15 Lac">14.5 Lac - 15 Lac</option>
<option value="15 Lac &amp; Above">15 Lac &amp; Above</option>
</select></td>
  </tr>
</table>
<div> <input type="button" onclick="addRow();"  value="Add More"/>
<input type="button" value="Remove" onclick="removeRow();" />
<input type="hidden" name="len" value="1" /></div>
<input name="submit" type="submit" value="submit" />
</fieldset>
</form>

i use this java script to add form fields

<script type="text/javascript">

function addRow() { var tbl = document.getElementById('tbltest'); var lastRow = tbl.rows.length; // if there's no header row in the table, then iteration = lastRow + 1 var iteration = lastRow; var row = tbl.insertRow(lastRow);

var cell = row.insertCell(0);
var sel = document.createElement('select');
sel.name = 'txtcategory' + iteration;
sel.id = 'id_str' + iteration;
sel.onchange = function (){ streamChange(iteration, this)   };
sel.options[0] = new Option('Stream','');
sel.options[1] = new Option('Management','Management');
sel.options[2] = new Option('Medical','Medical');
sel.options[3] = new Option('Dental','Dental');
sel.options[4] = new Option('Nursing','Nursing');
sel.options[5] = new Option('Ayurvedic','Ayurvedic');
sel.options[6] = new Option('Homeopathy','Homeopathy');
sel.options[7] = new Option('Unani','Unani');
sel.options[8] = new Option('Physiotherapy','Physiotherapy');
sel.options[9] = new Option('Pharmacology','Pharmacology');
sel.options[10] = new Option('Naturopathy & Yoga','Naturopathy & Yoga');
sel.options[11] = new Option('Engineering','Engineering');
sel.options[12] = new Option('Information Technology','Information Technology');
sel.options[13] = new Option('Computer / IT Training Institutes','Computer / IT Training Institutes');
sel.options[14] = new Option('Animation','Animation');
sel.options[15] = new Option('Polytechnic','Polytechnic');
sel.options[16] = new Option('Maritime','Maritime');
sel.options[17] = new Option('ITI','ITI');
sel.options[18] = new Option('Biotechnology','Biotechnology');
sel.options[19] = new Option('Law','Law');
sel.options[20] = new Option('Fashion Technology','Fashion Technology');
sel.options[21] = new Option('Hotel Management','Hotel Management');
sel.options[22] = new Option('Mass Media','Mass Media');
sel.options[23] = new Option('Distance Learning','Distance Learning');
sel.options[24] = new Option('Library Science','Library Science');
sel.options[25] = new Option('Degree Colleges','Degree Colleges');
sel.options[26] = new Option('B.Ed','B.Ed');
sel.options[27] = new Option('Fine Arts','Fine Arts');
sel.options[28] = new Option('Film Institutes','Film Institutes');
sel.options[29] = new Option('Tutorials','Tutorials');
sel.options[30] = new Option('Entrance Coaching','Entrance Coaching');
sel.options[31] = new Option('Vocational Courses','Vocational Courses');
sel.options[32] = new Option('Beautician Courses','Beautician Courses');
sel.options[33] = new Option('Language Courses','Language Courses');
sel.options[34] = new Option('Certificate Course','Certificate Course');
sel.options[35] = new Option('Schools','Schools');
sel.options[36] = new Option('International Schools','International Schools');
sel.options[37] = new Option('Private Schools','Private Schools');
sel.options[38] = new Option('Nursery / Play Homes','Nursery / Play Homes');
sel.options[39] = new Option('Flying Institutes','Flying Institutes');
sel.options[40] = new Option('Call Center Training','Call Center Training');
sel.options[41] = new Option('Sports Academy','Sports Academy');
sel.options[42] = new Option('10 + 2','10 + 2');
cell.appendChild(sel);

var cell2 = row.insertCell(1);
var el = document.createElement('input');
el.type = 'text';
el.name = 'txtcourse_name' + iteration;
el.id = 'id_cname' + iteration;
cell2.appendChild(el);

var cell4 = row.insertCell(2);
var el = document.createElement('input');
el.type = 'text';
el.style.width = '40px';
el.name = 'txtseat' + iteration;
el.id = 'id_seats' + iteration;
cell4.appendChild(el);

var cell8 = row.insertCell(3);
var sel = document.createElement('select');
sel.name = 'txtfees' + iteration;
sel.id = 'id_elig' + iteration;
sel.options[0] = new Option('Specify Fees','');
sel.options[1] = new Option('1 - 5000','1 - 5000');
sel.options[2] = new Option('5001 - 10000','5001 - 10000');
sel.options[3] = new Option('10001 - 20000','10001 - 20000');
sel.options[4] = new Option('20001 - 30000','20001 - 30000');
sel.options[5] = new Option('30001 - 40000','30001 - 40000');
sel.options[6] = new Option('40001 - 50000','40001 - 50000');
sel.options[7] = new Option('50001 - 60000','50001 - 60000');
sel.options[8] = new Option('60001 - 70000','60001 - 70000');
sel.options[9] = new Option('70001 - 80000','70001 - 80000');
sel.options[10] = new Option('80001 - 90000','80001 - 90000');
sel.options[11] = new Option('90001 - 1 Lac','90001 - 1 Lac');
sel.options[12] = new Option('1 Lac - 1.5 Lac','1 Lac - 1.5 Lac');
sel.options[13] = new Option('1.5 Lac - 2 Lac','1.5 Lac - 2 Lac');
sel.options[14] = new Option('2.5 Lac - 3 Lac','2.5 Lac - 3 Lac');
sel.options[15] = new Option('3.5 Lac - 4 Lac','3.5 Lac - 4 Lac');
sel.options[16] = new Option('4.5 Lac - 5 Lac','4.5 Lac - 5 Lac');
sel.options[17] = new Option('5.5 Lac - 6 Lac','5.5 Lac - 6 Lac');
sel.options[18] = new Option('6.5 Lac - 7 Lac','6.5 Lac - 7 Lac');
sel.options[19] = new Option('7.5 Lac - 8 Lac','7.5 Lac - 8 Lac');
sel.options[20] = new Option('8.5 Lac - 9 Lac','8.5 Lac - 9 Lac');
sel.options[21] = new Option('9.5 Lac - 10 Lac','9.5 Lac - 10 Lac');
sel.options[22] = new Option('10.5 Lac - 11 Lac','10.5 Lac - 11 Lac');
sel.options[23] = new Option('11.5 Lac - 12 Lac','11.5 Lac - 12 Lac');
sel.options[24] = new Option('12.5 Lac - 13 Lac','12.5 Lac - 13 Lac');
sel.options[25] = new Option('13.5 Lac - 14 Lac','13.5 Lac - 14 Lac');
sel.options[26] = new Option('14.5 Lac - 15 Lac','14.5 Lac - 15 Lac');
sel.options[27] = new Option('15 Lac & Above','15 Lac & Above');
cell8.appendChild(sel);
}
function removeRow()
{
  var tbl = document.getElementById('tbltest');
  var lastRow = tbl.rows.length;
  if (lastRow > 1) tbl.deleteRow(lastRow - 1);
}

and this is my php to insert the data into mysql

<?php
$dbc = mysql_connect('localhost', 'root', 'ziadpager');
if (!$dbc)
{
    die('could not connect: '.mysql_error());
}
mysql_select_db ('a360', $dbc);
if(isset($_POST['submit']))
{
    $length = mysql_real_escape_string($_POST['len']);
    //$institute_id= 1;
    for($loop=0; $loop<=$length; $loop++)
    {
        $category = "txtcategory".$loop;
        $course_name = "txtcourse_name".$loop;
        $seat = "txtseat".$loop;
        $fees = "txtfees".$loop;
            $cat = mysql_real_escape_string($_POST[$category]);
            $cou = mysql_real_escape_string($_POST[$course_name]);
            $sea = mysql_real_escape_string($_POST[$seat]);
            $fee = mysql_real_escape_string($_POST[$fees]);
        $store = "INSERT INTO institute_courses (course_id, category, course_name, seats, fees) VALUES (NULL, '$cat', '$cou', '$sea', '$fee')";
        $go = mysql_query($store);
    }
}

?>

the problem is when i have a value of 1 in my hidden field i am able to insert only two set of values to mysql database

<input type="hidden" name="len" value="1" /></div>

and if i increase the value to say 10

<input type="hidden" name="len" value="10" /></div>

and if i dont put in 10 sets of data i get this error

Notice: Undefined index: txtcategory2 in C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\site\addcourses3_1.php on line 18

Notice: Undefined index: txtcourse_name2 in C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\site\addcourses3_1.php on line 19

Notice: Undefined index: txtseat2 in C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\site\addcourses3_1.php on line 20

Notice: Undefined index: txtfees2 in C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\site\addcourses3_1.php on line 21

so on...

Please advice on what i am doing wrong, the users should be able to put in as many or as little data into the database without any error.

Please do help thanks in advance

The problem is

$length = mysql_real_escape_string($_POST['len']);
//$institute_id= 1;
for($loop=0; $loop<=$length; $loop++)

You work out the loop's length to be exactly the value of that hidden field. You need to either work out the length in a different way, e.g. a while test checking if there's data left, or else use javascript to update the field.

Edit

Unless I'm missing something, your HTML code only sends one selected option. If so you do not want to write several into the database - because you don't have the data.

To transmit several rows you'd have to:

(1) use <select ... multiple >

(2) Find some way of knowing how manay rows, either through Javascript or after the data's been sent

(3) Use that count in place of length.