Codeigniter - How to create a form with undefined number of input? - php

Question

So I've been trying to create an 'add' function for a contest table that is also linked to a joining table as the contest has many sport events associated to it (and a sport events will also be included in many contests). I have managed to create it as below, however it is limited to only adding one row into the joining table based on the chosen game in a dropdown.
So now, how do I go about creating the form if I don't know how many sport events there might be? How will the website create another dropdown if one dropdown is used so that more sport events can be selected? Similarly, how does the controller know that there are x amount of dropdowns selected, and hence x amount of rows to be added to the joining table?
I'm sorry if I am using incorrect or ambiguous terms to describe my problem. I have only started learning and creating websites recently.
Thank you.
UPDATE: I may have a solution per the updated codes below. However I am now stuck on the inserting into the database page. For some reason when I click submit, the next page loads but with no error and no rows inserted. Please help :)
View
<h1>Add New Contest</h1>
<?php
echo form_open('contests/add/');
?>
<?php
echo "<br />" "<br />"
echo "Contest Name";
$data = array( 'name' => 'contest_name',
'value' => set_value('contest_name'),
);
echo form_input($data);
echo "<br />" "<br />"
echo "Game";
?>
<div class="field_wrapper">
<div>
<select name="field_name[]">
<option value="" disabled selected>Select Game</option>
<?php
foreach($events_lists->result() as $row) {
$sports_events_id = $row->sports_events_id;
$sports_events_start_date = $row->sports_events_start_date;
$sports_events_start_time = $row->sports_events_start_time;
$home_team_shorthand = $row->home_team_shorthand;
$away_team_shorthand = $row->away_team_shorthand;
?>
<option value="<?php echo $sports_events_id; ?>"><?php echo $home_team_shorthand; ?> v <?php echo $away_team_shorthand; ?> - <?php echo $sports_events_start_date; ?> <?php echo $sports_events_start_time; ?></option>
<?php } ?>
</select>
<img src="add-icon.png"/>
</div>
</div>
<?php
echo "<br />" "<br />"
$data = array( 'value' => 'Add Contest',
'name' => 'submit',
'class' => 'submit-btn',
);
echo form_submit($data);
echo form_close();
?>
Controller
function add()
{
$league_id = $this->uri->segment(3);
$this->load->module('leagues');
$data['leagues_list'] = $this->leagues->get_where($league_id);
foreach ($data['leagues_list']->result() as $row) {
$league_insert_id = $row->id;
$this->load->module('sports_events');
$data['events_lists'] = $this->sports_events->get_events_list($league_insert_id);
}
if ($this->form_validation->run() == FALSE) {
$data['view_file'] = 'add_contest';
$this->load->module('template');
$this->template->cmslayout($data);
} else {
$data1 = array(
'contest_name' => $this->input->post('contest_name')
);
if(isset($_REQUEST['submit'])) {
$data2 = $_REQUEST['field_name'];
}
if ($this->_transactions_new_contest($data1, $data2)) {
return $query;
$this->session->set_flashdata('team_phase_created', 'The team phase has been set');
redirect('/contests/');
}
}
}
Model
function _transactions_new_contest($data1, $data2){
$this->db->trans_start();
$this->db->insert('contests', $data1);
$contest_id = $this->db->query('SELECT contests.id FROM contests ORDER BY contests.id DESC limit 1');
foreach ($contest_id->result() as $row) {
$contest_result_id = $row->id;
foreach($data2 as $value){
$this->db->query('INSERT INTO contests_has_sports_events (contests_id, sports_events_id) VALUES (' . $contest_result_id . ', ' . $value . ')');
} }
$this->db->trans_complete();
}