Multiple images are not uploaded using jquery ajax in codeigniter - php

Question

In my code I have an input field having name product_image where I want to upload and insert multiple files into my database like this img1.jpg,img2.jpg,img3.jpg. But Now, what happen when I select 4 files i.e. img1.jpg,img2.jpg,img3.jpg,img4.jpg only img4.jpg store in my database and only this file are moving in my folder.
view:
<script>
$(document).ready(function(){
$("#submit").click(function(e){
e.preventDefault();
product_name = $("#product_name").val();
var formData = new FormData();
$.each($("#product_image"), function (i, obj) {
$.each(obj.files, function (j, file) {
formData.append('product_image[' + i + ']', file);
});
});
formData.append('product_name', product_name);
$.ajax({
type:"POST",
data:formData,
processData: false,
contentType: false,
url:"<?php echo base_url(); ?>admin/products",
success:function(data){
$("#success_upload").html(data);
}
});
});
});
</script>
<input type="text" class="form-control" id="product_name" name="product_name">
<input type="file" id="product_image" name="product_image[]" multiple>
<input type="submit" class="btn btn-primary" id="submit" name="submit">
Controller:
public function products()
{
$dataInfo = array();
$files = $_FILES;
$cpt = count($_FILES['product_image']['name']);
for($i=0; $i<$cpt; $i++)
{
$_FILES['product_image']['name']= $files['product_image']['name'][$i];
$_FILES['product_image']['type']= $files['product_image']['type'][$i];
$_FILES['product_image']['tmp_name']= $files['product_image']['tmp_name'][$i];
$_FILES['product_image']['error']= $files['product_image']['error'][$i];
$_FILES['product_image']['size']= $files['product_image']['size'][$i];
$this->upload->initialize($this->set_upload_options());
$this->upload->do_upload('product_image');
$upload_data = $this->upload->data();
$name_array[] = $upload_data['file_name'];
$fileName = $upload_data['file_name'];
$images[] = $fileName;
}
$fileName = $images;
$data = array(
'product_name' => $this->input->post('product_name'),
'product_image' => implode(",",$fileName),
);
$sql = $this->db->insert('add_product',$data);
if($sql == true)
{
echo '<p style="color:green;">New Product Added</p>';
}
else
{
echo '<p style="color:red;">Unable to Proceed!</p>';
}
}
private function set_upload_options()
{
$config = array();
$config['upload_path'] = FCPATH.'resource/product/';
$config['allowed_types'] = 'gif|jpg|png|jpeg';
$config['max_size'] = '1024';
$config['overwrite'] = FALSE;
return $config;
}
So, How can I upload and insert multiple files into my database? Please help me.
Thank You