CODEIGNITER: Check if exist - php

Question

I have table ingredient w/c consist of(ingredient_id,name),category w/c consist of(category_id,name) and category_ingredients w/c consist of(ingredient_id,category_id). I created a form for adding many ingredients by category and It check if 1 or more ingredients already exists in that category then I will only have to get the id's of the ingredient and then the other ingredients that don't exist will be inserted in my DB. Please help me i really need your help :(
VIEW:
<?php echo form_open('dashboard/uploadIngredients', 'class="form-horizontal" enctype="multipart/form-data"'); ?>
<div class="form-group">
<div class="col-sm-10">
<select required class="form-control" name="ingredient_category">
<option value="" selected disabled>Select Ingredient Category</option>
<option value="All">All</option>
<?php foreach($this->products_model->getCategory() as $row): ?>
<option value="<?php echo $row->category_id ?>"><?php echo $row->category_name; ?></option>
<?php endforeach; ?>
</select>
</div>
</div>
<div class="form-group">
<div class="col-sm-10">
<textarea class="form-control" name="ingredients" rows="5" placeholder="Ingredients (EX. onion, oil, pasta)" required></textarea>
</div>
</div>
<div class='form-group'>
<div class="col-sm-10">
<button class="btn btn-lg btn-positive" type="submit"><i class="glyphicon glyphicon-ok"></i> Save Ingredient</button>
</div>
</div>
<?php echo form_close(); ?>
CONTROLLER:
public function uploadIngredients(){
foreach(explode(',', $this->input->post('ingredients')) as $key => $value)
{
if (!$this->products_model->getIngredientByName($value)) {
$saveData[] = array(
'ingredient_id' => null,
'name' => trim($value)
);
}
}
$ingredient_id = $this->products_model->saveIngredients($saveData);
foreach (explode(',', $this->input->post('ingredient_category')) as $key => $value)
{
foreach ( $ingredient_id as $key => $str ){
$joinData[] = array(
'ingredient_id' => $str,
'category_id' => intval($value)
);
}
$this->products_model->saveCategoryIngredients($joinData);
redirect('dashboard/add_ingredients');
}
MODEL:
public function saveIngredients($ingredient_id)
{
foreach($ingredient_id as $row => $value) {
$query=$this->db->where('ingredient_id', $value->ingredient_id);
$this->db->insert('ingredient', $value);
$insert_id[] = $this->db->insert_id();
}
return $insert_id;
}
public function getIngredientByName($name) {
$this->db->select('ingredient_id');
$this->db->limit(1);
$this->db->where('category_id', $category_id);
$ingredientQuery = $this->db->get('category_ingredient');
$ingredient_id = $ingredientQuery->row()->ingredient_id;
$this->db->select('name');
$this->db->where('ingredient_id', $ingredient_id);
$query = $this->db->get('ingredient');
foreach($query->result() as $row)
{
return $row->name;
}
}