Codeigniter Abstract Module

MY_Model.php

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

abstract class MY_Model extends CI_Model {

private $file_dest;
private $table;
private $fields;
private $field_values;
	
public function __construct() {
  parent::__construct();
	
  $this->load->database();
  $this->load->helper(array('date', 'html'));
  $this->load->library(array('ion_auth'));
  $this->table = (string) '';
  $this->fields = array();
  $this->field_values = '';
  $this->file_dest = '';

}
	
//Retrieves table's field meta
public function get_field_meta($table_name) {
  $this->table = $table_name;
  return $this->db->field_data($this->table);
}
	
//reads data from table when a condition is met
public function read_values_where($table_name, $condition=NULL, $field=NULL) {

  $this->table = strtolower($table_name);
  $field_name = (!isset($field) ? "id" : $field);
		
  $sql = "SELECT * FROM `$table_name` ";
	
  if(isset($condition)) {
	$sql .= "WHERE $field = '$condition'";
  }
	
  $sql .= ";";
  $query = $this->db->query($sql);
  
  return $query->num_rows() > 0 ? $query->result_array() : FALSE;

}	

public function create_update_logic($table_name,$operation,$record=NULL,$field=NULL) {

  $this->table = $table_name;
  $write = fopen("insert_data.txt", "a");
	//path to image upload directory
  $this->file_dest = realpath(str_replace('system', 'assets/img', BASEPATH));
  $path = $this->file_dest.'/'.strtolower($this
                                          ->uri
                                          ->segment(2));
	
	//loop through table's fields and retrieve metadata
  foreach($this->get_field_meta($this->table) as $field) {
		//id is pk, auto-increment
	if($field->name != "id")  {
	  if(substr($field->name, 0, -2) == "image") {
		//if upload destination does not exist
		if(!is_dir($path)) {
		  @mkdir($path, 0777);
		}
		for($k = 1; $k <= count($_FILES); $k++) {
		  $file = $path.'/'.$_FILES['userfile_'.$k]['name'];
		  if(move_uploaded_file($_FILES['userfile_'.$k]['tmp_name'], $file)) {
			$upload_val = "'".base_url()."assets/img/".$this
			                                           ->uri
                                                                   ->segment(2)
			$upload_val .= '/'.$_FILES['userfile_'.$k]['name']."'";
						
			$this->fields[] = "`image_".$k."`";
			$this->field_values[] = $upload_val;
							
		  } 
		  else {
			ob_start();
			$errors = $_FILES['userfile_'.$k]['errors'];
			$out = print_r($errors);
			fwrite($write, $out);
			ob_end_clean();
		  }
		}
	   }
	   else {
		 $this->fields[] = $field->name;
		 $postVal = $this->input->post($field->name);
		 
		 if(is_numeric($postVal)) {
		   if(strpos("date", $field->name)) {
			 $this->field_values[] = date('Y-m-d H:i:s', strtotime($postVal));
		   } 
		   else {
			 $this->field_values[] = mysql_real_escape_string($postVal);
		   }	
		 }
		 else {
			$this->field_values[] = "'".mysql_real_escape_string($postVal)."'";
		 }
	    }
	  }
	}
	if($operation == "add") {
	  $sql = "INSERT INTO `$this->table` ";
	  $sql .= "(".implode(', ', $this->fields).") ";
	  $sql .= "VALUES (".implode(', ', $this->field_values).")";
	  fwrite($write, $sql);
	}
	if($operation == "edit" ) {
	  $field_count = count($this->fields);
			
	  $sql = "UPDATE $this->table ";
	  $sql .= "SET ";
			
	  for($i=0; $i <= $field_count - 1; $i++) {
	    $sql .= $this->fields[$i]." = ".$this->field_values[$i];
		$i != $field_count - 1  ? $sql .= ", " :  $sql .= " ";
	  }
	  if(!is_numeric($this->uri->segment(3)))) {
		throw new Exception("Improperly formatted URL");
	  }
	  else {
	    $sql .= "WHERE id = '$record;";
	  }
   }
    return $this->db->query($sql);
}

public function destroy($table ,$field_id, $row_id) {
	
  $row_id = str_replace('_', ' ', $row_id);
  
  foreach(MY_Model::get_field_meta($table) as $field) {
	if($field->name == "image") {
	  $sql = "SELECT image from $table;";
	  $query = $this->db->query($sql);
	
	  if($query->num_rows() > 0) {
		foreach($query->result() as $q) {
		  $data[] = $q;
		}
		unlink($data);
	  }
	}
  }
  $sql = "DELETE FROM $table ";
  $sql .= "WHERE $field_id = '$row_id';";
  
  return $this->db->query($sql);
}

}
?>