Opencart: Error No:1062 Duplicate entry '1' for key 'PRIMARY' - php

Question

I'm developing a carousel extension for opencart that has Item ID, Item Name, Link, Image, Sort Order. The carousel had an issue while saving it will change the item id so I had to modify the code to get fixed ID queryed to the DB, however now I get the 1062 Error.
Notice: Error: Duplicate entry '1' for key 'PRIMARY' Error No: 1062
INSERT INTO crousal SET crousal_id = '1', name = 'Baby & Toys', link =
'/index.php?route=product/product&product_id=7570', image =
'data/carousel/banner2.jpg', sort_order = '0' in
/home/user/public_html/system/database/mysql.php on line 49
Sharing the model/carousel.php editCarousel Function
public function editCrousal($crousal_image) {
$crousal_id = $this->db->getLastId();
$this->db->query("DELETE FROM " . DB_PREFIX . "mobiapp_crousal WHERE crousal_id = '" . (int)$crousal_id . "'");
if (isset($crousal_image['crousal_image'])) {
foreach ($crousal_image['crousal_image'] as $crousal_image) {
$this->db->query("INSERT INTO " . DB_PREFIX . "mobiapp_crousal SET crousal_id = '" . (int)$crousal_id . "', name = '" . $this->db->escape($crousal_image['name']) . "', link = '" . $this->db->escape($crousal_image['link']) . "', image = '" . $this->db->escape($crousal_image['image']) . "', sort_order = '" . (int)$crousal_image['sort_order'] . "'");
$crousal_id = $this->db->getLastId();
}
}
}
Any advice why I'm getting this error and how to resolve, thank you in advanced.
P.S.: Opencart 1.5.x
Edited: DB Structure & Module info
$this->db->query("
CREATE TABLE IF NOT EXISTS `" . DB_PREFIX . "mobiapp_crousal` (
`crousal_id` INT(11) NOT NULL AUTO_INCREMENT,
`name` VARCHAR(255) NOT NULL,
`link` VARCHAR(255) NOT NULL,
`image` VARCHAR(255) NOT NULL,
`sort_order` INT(3) NOT NULL,
PRIMARY KEY (`crousal_id`)
) ENGINE=MyISAM DEFAULT COLLATE=utf8_general_ci;");
Model File
public function addCrousal($crousal_image) {
$this->db->query("INSERT INTO " . DB_PREFIX . "mobiapp_crousal SET name = '" . $this->db->escape($crousal_image['name']) . "', sort_order = '" . (int)$crousal_image['sort_order'] . "'");
$crousal_id = $this->db->getLastId();
if (isset($crousal_image['crousal_image'])) {
foreach ($crousal_image['crousal_image'] as $crousal_image) {
$this->db->query("INSERT INTO " . DB_PREFIX . "mobiapp_crousal SET crousal_id = '" . (int)$crousal_id . "', link = '" . $this->db->escape($crousal_image['link']) . "', image = '" . $this->db->escape($crousal_image['image']) . "'");
$crousal_id = $this->db->getLastId();
}
}
}
public function editCrousal($crousal_image) {
$crousal_id = $this->db->getLastId();
$this->db->query("DELETE FROM " . DB_PREFIX . "mobiapp_crousal WHERE crousal_id = '" . (int)$crousal_id . "'");
if (isset($crousal_image['crousal_image'])) {
foreach ($crousal_image['crousal_image'] as $crousal_image) {
$this->db->query("INSERT INTO " . DB_PREFIX . "mobiapp_crousal SET crousal_id = '" . (int)$crousal_id . "', name = '" . $this->db->escape($crousal_image['name']) . "', link = '" . $this->db->escape($crousal_image['link']) . "', image = '" . $this->db->escape($crousal_image['image']) . "', sort_order = '" . (int)$crousal_image['sort_order'] . "'");
$crousal_id = $this->db->getLastId();
}
}
}
public function getCrousalImages() {
$crousal_image_data = array();
$crousal_image_query = $this->db->query("SELECT * FROM " . DB_PREFIX . "mobiapp_crousal ORDER BY sort_order ASC");
foreach ($crousal_image_query->rows as $crousal_image) {
$crousal_image_description_data = array();
$crousal_image_description_query = $this->db->query("SELECT * FROM " . DB_PREFIX . "mobiapp_crousal WHERE crousal_id = '" . (int)$crousal_image['crousal_id'] . "'");
$crousal_image_data[] = array(
'crousal_image' => $crousal_image,
'link' => $crousal_image['link'],
'name' => $crousal_image['name'],
'crousal_id' => $crousal_image['crousal_id'],
'image' => $crousal_image['image'],
'sort_order' => $crousal_image['sort_order']
);
}
return $crousal_image_data;
}

Answer 1

I did review for this module. Seems like this module has totally wrong structure. As you can see in method addCrousal foreach-statement with insertion to database. But in this insert carousal_id not incrementing so in the table will be records with not unique carousal_id. So this column can't be PRIMARY.
I suggest you to rewrite module with two tables "Slides" with relations (has many) "Images". Or you can remove PRIMARY index and operation will pass but it's not true solution.