<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class General_model extends CI_Model
{
    public function __construct()
    {
        parent::__construct();
    }

    // Return all records in the table
    public function get_all($table)
    {
        $q = $this->db->get($table);
        if($q->num_rows() > 0)
        {
            return $q->result();
        }
        return array();
    }

    // Return only one row
    public function get_row($table,$primaryfield,$id)
    {
        $this->db->where($primaryfield,$id);
        $q = $this->db->get($table);
        if($q->num_rows() > 0)
        {
            return $q->row();
        }
        return false;
    }

    // Return one only field value
    public function get_data($table,$primaryfield,$fieldname,$id)
    {
        $this->db->select($fieldname);
        $this->db->where($primaryfield,$id);
        $q = $this->db->get($table);
        if($q->num_rows() > 0)
        {
            return $q->result();
        }
        return array();
    }

    // Insert into table
    public function add($table,$data)
    {
        return $this->db->insert($table, $data);
    }

    // Update data to table
    public function update($table,$data,$primaryfield,$id)
    {
        $this->db->where($primaryfield, $id);
        $q = $this->db->update($table, $data);
        return $q;
    }

    // Delete record from table
    public function delete($table,$primaryfield,$id)
    {
    	$this->db->where($primaryfield,$id);
    	$this->db->delete($table);
    }

    // Check whether a value has duplicates in the database
    public function has_duplicate($value, $tabletocheck, $fieldtocheck)
    {
        $this->db->select($fieldtocheck);
        $this->db->where($fieldtocheck,$value);
        $result = $this->db->get($tabletocheck);

        if($result->num_rows() > 0) {
            return true;
        }
        else {
            return false;
        }
    }

    // Check whether the field has any reference from other table
    // Normally to check before delete a value that is a foreign key in another table
    public function has_child($value, $tabletocheck, $fieldtocheck)
    {
        $this->db->select($fieldtocheck);
        $this->db->where($fieldtocheck,$value);
        $result = $this->db->get($tabletocheck);

        if($result->num_rows() > 0) {
            return true;
        }
        else {
            return false;
        }
    }

    // Return an array to use as reference or dropdown selection
    public function get_ref($table,$key,$value,$dropdown=false)
    {
        $this->db->from($table);
        $this->db->order_by($value);
        $result = $this->db->get();

        $array = array();
        if ($dropdown)
            $array = array("" => "Please Select");

        if($result->num_rows() > 0) {
            foreach($result->result_array() as $row) {
            $array[$row[$key]] = $row[$value];
            }
        }
        return $array;
    }
}

This is a common model used to run some common functions like CRUD functions, get reference data from table, check for dependencies etc. So in other model, we don't have to add those function repeatedly

Commonly used db functions for CodeIgniter

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