My base model class for my CodeIgniter-based cms.

MY_Model.php

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * My Model
 *
 * Used as a base class for all admin or app related model functions.
 *
 * @author Alex Garcia
 * @since 0.1
 * @version 1
 */
class MY_Model extends CI_Model{

	/**
	 * An array of fields defined in the database table. Do not include the id
	 * field which is a primary key.
	 *
	 * Usage: $this->db_fields = array('column_name','column_name2');
	 *
	 * @var array
	 */
	public $db_fields;

	//--------------------------------------------------------------------------

	/**
	 * The name of the database table we want to work with.
	 *
	 * Usage: $this->db_table = 'name_of_table';
	 *
	 * @var string
	 */
	public $db_table;
	
	//--------------------------------------------------------------------------
	
	/**
	 *  An array of models that the current model requires.
	 * $this->db_requires = array('module_name'=>array('model_name','model_name));
	 * 
	 * @var array
	 */
	public $db_requires;
	
	/**
	 * The name of the module we are working with.
	 * 
	 * @var string
	 */
	public $module;
	
	//--------------------------------------------------------------------------
	
	/**
	 * The name of the current method.
	 * 
	 * @var string
	 */
	public $method;
	
	//--------------------------------------------------------------------------
	
	/** 
	 * The id segment from the uri.
	 * 
	 * @var mixed 
	 */
	public $id;

	//--------------------------------------------------------------------------

	/**
	 * The constructor sets the fields property to a an empty array.
	 */
	public function __construct()
	{
		parent::__construct();
		$this->db_fields = array();
	}
	
	//--------------------------------------------------------------------------

	/**
	 * Finds a set of records.
	 *
	 * If an id is present it will return that single record as an array.
	 * If the orderby array argument is present it will order the result based on
	 * the first and second indexes in the array.
	 *
	 * Usage: $this->model_name->find();
	 * Usage: $this->model_name->find(1);
	 * Usage: $this->model->name->find(NULL, array('column_name','asc')) or desc.
	 * Usage: $this->model->name->find(NULL, array('column_name','asc'), 'id, first_name, last_name')
	 * 
	 * @param int $id An optional id to return a single record.
	 * @param array $orderby An array with column and sort direction. array('column'=>'asc')
	 * @param string $select A string with the columns to select. 'id, first_name, last_name'
	 * @return array
	 */
	public function find($id = NULL, $orderby = NULL, $select = NULL)
	{
		if ( $id == NULL )
		{
            if ( $orderby != NULL )
			{
           		$this->db->order_by($orderby[0], $orderby[1]);
           	}

			if ($select != NULL)
			{
				$this->db->select($select);
			}

            $result = $this->db->get($this->db_table);
			
			if ($result->num_rows() > 0)
			{
				return $result->result_array();
			}
			else
			{
				return array();
			}
		}
		else
		{
			if ($select != NULL)
			{
				$this->db->select($select);
			}

			$this->db->where('id',$id);
			
			$result = $this->db->get($this->db_table);

			if ($result->num_rows() > 0)
			{
				return $result->row_array();
			}
			else
			{
				return array();
			}
		}
	}

	//--------------------------------------------------------------------------

	/**
	 * Finds a set of record for pagination.
	 * 
	 * @param int $limit The number of records to return.
	 * @param int $offset Where to start the next set of records.
	 * @param array $orderby An array containing the column and direction to order the results by.
	 * @param string $select A string of column names to select.
	 */

	public function find_count($limit = NULL, $offset = 0, $orderby = NULL, $select = NULL)
	{
		$total_rows = $this->count();
		if ($limit == NULL) 	$limit = app('app_total_records');
        if ($orderby != NULL) 	$this->db->order_by($orderby[0], $orderby[1]);
		if ($select != NULL) 	$this->db->select($select);
		
		$result = $this->db->get($this->db_table, $limit, $offset);
		return array('total_rows'=>$total_rows,'result'=>$result->result_array());
	}
	
	//--------------------------------------------------------------------------

	/**
	 * Finds a set of records where the condition in column name and column
	 * value is true.
	 *
	 * Usage: $this->model_name->find_where('status','published');
	 * Usage: $this->model_name->find_where('status !=','archived');
	 *
	 * @param string $column_name The name of the column for our condtion.
	 * @param string $column_value The value of the column for our condition.
	 * @return array
	 */
	public function find_where($column_name, $column_value)
	{
			$this->db->where($column_name,$column_value);
			$result = $this->db->get($this->db_table);
			return $result->result_array();
	}

	//--------------------------------------------------------------------------

	/**
	 * Saves a record to the database either as an insert or update.
	 *
	 * This is a massive function that also handles our workflow. Below is an
	 * explanation of how the workflow ties into this function.
	 *
	 * @param array $data An array of data that we want to save.
	 * @param int $id The primary key of a record we are updating.
	 * @return boolean
	 */
    public function save($data = NULL, $id = NULL)
	{	
 		if (! is_null($data)) 
		{
      		$data = array_merge($this->prep_form_data('save'), $data);	
      	}
		else
		{
      		$data = $this->prep_form_data('save');
      	}

        if ($id == NULL)
		{   
			$result = $this->db->insert($this->db_table, $data);
			return $result;
		}
		else
		{
			$this->db->where('id', $id);
			$result = $this->db->update($this->db_table,$data);
			return $result;
		}
	}
	
	//--------------------------------------------------------------------------

	/**
	 * Saves a core record to the database either as an insert or update.
	 *
	 * This is a massive function that also handles our workflow. Below is an
	 * explanation of how the workflow ties into this function.
	 *
	 * @param array $data An array of data that we want to save.
	 * @param int $id The primary key of a record we are updating.
	 * @return boolean
	 */
    public function save_direct($data, $id = NULL)
	{   
        if ($id == NULL)
        {   
            $result = $this->db->insert($this->db_table, $data);
            return $result;
        }
        else
        {
           	$this->db->where('id',$id);
            $result = $this->db->update($this->db_table,$data);
          	return $result;
        }
	}

	//--------------------------------------------------------------------------

	/**
	 * Deletes a record from the database.
	 *
	 * @param int $id The id of the record we want to delete.
	 * @return boolean
	 */
	public function delete($id)
	{
		$this->db->where('id', $id);
		return $this->db->delete($this->db_table);
	}

	//--------------------------------------------------------------------------

	/**
	 * Returns the count of records for a table. We can filter that result
	 * by providing a column and value to create a condition.
	 *
	 * @param string $column The table column.
	 * @param string $value The table value.
	 * @return int The number of records.
	 */
	public function count($column = NULL, $value = NULL)
	{
		if($column != NULL AND $value != NULL)
        {
            $this->db->where($column,$value);
        }

        $result = $this->db->get($this->db_table);
		return $result->num_rows();
	}

	//--------------------------------------------------------------------------

	/**
	 * Returns the count of records for a table. We can filter that result
	 * by providing a column and value to create a condition.
	 *
	 * @param string $column The table column.
	 * @param string $value The table value.
	 * @return int The number of records.
	 */
	public function count_where($conditions = array())
	{
		foreach($conditions as $column=>$value)
		{
			$this->db->where($column,$value);
		}

        $result = $this->db->get($this->db_table);
		return $result->num_rows();
	}

	//--------------------------------------------------------------------------

	/**
	 * Provides a way to perform searches of data.
	 * 
	 * @param string $query A string of words seperated by commas.
	 * @param array $fields An array of fields to search.
	 * @param string $table The name of the table to search in.
	 * @return array
	 */
	public function search($query, $fields = NULL, $table = NULL)
	{
		$query = explode(',',$query);

		if ($table == NULL)
		{
			$table = $this->db_table;
		}

		if ($fields == NULL)
		{
			$fields = $this->db_fields;
		}

		foreach($query as $term)
		{
			foreach($fields as $field)
			{
				//$this->db->select($field);
				$this->db->or_like($field, $term);
			}

			$result[$term] = $this->db->get($table)->result_array();
		}

		return $result;
	}
	
	//--------------------------------------------------------------------------
	
	/**
	 * Exports the current table into csv.
	 *
	 * @return void
	 */
	public function export()
	{
		$this->load->helper(array('file','download'));
		$this->load->dbutil();
		$result = $this->db->get($this->db_table);
		$data = $this->dbutil->csv_from_result($result);
		$ts = time();
		force_download('log_'. $ts .'.csv', $data);
	}

	//--------------------------------------------------------------------------
	
	/**
     * Preps our fields for our views and/or for our save method. This relies
     * on the db_fields being defined in the model class for each model.
     *
     * @param string $action The default is create. Can also be save or update.
	 * @param array $model Passed to function like: $this->name_of_model->find($id)
	 * @param array $exclude An array of additional fields to exclude.
     * @return array $view_data An array of fields prepped as empty or with data from our form.
     */
    public function prep_form_data($action = 'create', $model = NULL, $exclude = array())
    {
		if ($action == 'create')
        {
            foreach($this->db_fields as $field)
            {
                $view_data[$field] = '';
            }
        }
        elseif($action == 'save')
        {
            foreach($this->db_fields as $field)
            {
                
                if ( ! in_array($field, $exclude))
                {
                    if (isset($field))
                    {
                        $view_data[$field] = $this->input->post($field);
                    }
                    else
                    {
                        $view_data[$field] = '';
                    }
                }	
			}
        }
        elseif($action == 'update')
        {
            foreach($this->db_fields as $field)
            {
                if (isset($model[$field]))
				{
					$view_data[$field] = $model[$field];
				}
				else
				{
					$view_data[$field] = '';
				}
            }
        }
        return $view_data;
    }
	
	//--------------------------------------------------------------------------

	/**
	 * Finds a set of records for our form.
	 *
	 * If an id is present it will return that single record as an array.
	 * If the order by array argument is present it will order the result based on
	 * the first and second indexes in the array.
	 *
	 * Usage: $this->model_name->find_form();
	 * Usage: $this->model_name->find_form((array) $data);
	 * Usage: $this->model->name->find_form((array) $data, 1);
	 *
	 * @param array $merge_data An array of additional data to merge with our db result to pass to our form.
	 * @param int $id An optional id to return a single record.
	 * @return array
	 */
	public function find_form($merge_data = NULL, $id = NULL)
	{
		if ($id == NULL)
		{
            foreach($this->db_fields as $field)
            {
                $view_data[$field] = '';
            }
		}
		else
		{
			$this->db->where('id',$id);
			$result = $this->db->get($this->db_table);
			if ($result->num_rows() > 0)
			{
				$result = $result->row();
								
				foreach($this->db_fields as $field)
	            {
	                $view_data[$field] = $result->$field;
				}
			}
			else
			{
				return array();
			}
		}
		
		if ($merge_data != NULL)
		{
			$view_data = array_merge($view_data, $merge_data);
		}
		return $view_data;
	}

	//--------------------------------------------------------------------------

	/**
	 * Clears the database cache.
	 * 
	 * @return void
	 */
	public function clear_cache()
	{
		$this->db->cache_delete($this->module, $this->db_table);
	}
}