Base_Model for CodeIgniter. The idea is taken from Laravel's Eloquent ORM

base_model.php

<?php
/**
 * Base Model to provide ORM-like CRUD operation wrapper
 * Version: 1.1
 */
class Base_Model extends CI_Model {
	protected $table = "";
	protected $primary = "id";
	protected $per_page = 20;
	protected $order = "";

	protected $default_filter = array();

	function __construct()
	{
		parent::__construct();

		$this->load->database();
	}

	/**
	 * Set default WHERE clause for each SELECT query
	 * @param $field string Field name
	 * @param $value string Value of the field
	 */
	function set_default_filter($field, $value)
	{
		$this->default_filter[$field] = $value;
	}

	/**
	 * Implement each $default_filter set above
	 * To be called in every method which generate SELECT query
	 * @access protected
	 * @return void
	 */
	protected function default_filter()
	{
		if(empty($this->default_filter)) return;

		foreach ($this->default_filter as $field => $value)
			$this->db->where($field, $value);
	}

	/**
	 * Run a query to database after implementing the default filter
	 * Return the query object to be processed further by its caller
	 * @access private
	 * @param	int		page	The current pagination to get
	 * @return	CodeIgniter query object
	 * @see this::default_filter
	 */
	private function query($page = 1)
	{
		$this->default_filter();

		if(!empty($this->per_page))
		{
			$offset = ($page - 1) * $this->per_page;
			if($offset < 0) $offset = 0;

			$this->db->limit( $this->per_page, $offset );
		}

		if(!empty($this->order))
			$this->db->order_by( $this->order );
		else
			$this->db->order_by( $this->primary, 'desc' );

		return $this->db->get( $this->table );
	}

	function lists($page = 1)
	{
		$query = $this->query($page);

		return $query->num_rows > 0 ? $query->result() : array();
	}

	function first()
	{
		$query = $this->query();

		return $query->num_rows > 0 ? $query->row() : array();
	}

	/**
	 * Find a row using primary key
	 * @param id The "ID" to find. Uses column which defined in $primary property above
	 * @return stdClass|null
	 */
	function find($id)
	{
		$this->default_filter();

		$query = $this->db->get_where( $this->table, array($this->primary => $id) );
		return $query->num_rows == 1 ? $query->row() : null;
	}

	function count()
	{
		$this->default_filter();

		return $this->db->get($this->table)->num_rows();
	}

	function save($data)
	{
		if(is_object($data)) $data = json_decode(json_encode($data), true);

		if(!isset($data[ $this->primary ]) or empty($data[ $this->primary ]))
			return $this->db->insert( $this->table, $data );
		else
			return $this->db->update( $this->table, $data, array($this->primary => $data[ $this->primary ]) );
	}

	function delete($id)
	{
		return $this->db->delete($this->table, array($this->primary => $id));
	}
}