diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index 9b44e7c..0295b9d 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -1,13 +1,13 @@
-<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP 5.2.4 or newer
  *
  * NOTICE OF LICENSE
- * 
+ *
  * Licensed under the Open Software License version 3.0
- * 
+ *
  * This source file is subject to the Open Software License (OSL 3.0) that is
  * bundled with this package in the files license.txt / license.rst.  It is
  * also available through the world wide web at this URL:
@@ -25,8 +25,6 @@
  * @filesource
  */
 
-// ------------------------------------------------------------------------
-
 /**
  * PDO Database Adapter Class
  *
@@ -42,28 +40,28 @@
  */
 class CI_DB_pdo_driver extends CI_DB {
 
-	var $dbdriver = 'pdo';
+	public $dbdriver = 'pdo';
 
 	// the character used to excape - not necessary for PDO
-	var $_escape_char = '';
+	protected $_escape_char = '';
 
 	// clause and character used for LIKE escape sequences
-	var $_like_escape_str;
-	var $_like_escape_chr;
+	protected $_like_escape_str;
+	protected $_like_escape_chr;
 
 	/**
 	 * The syntax to count rows is slightly different across different
 	 * database engines, so this string appears in each driver and is
 	 * used for the count_all() and count_all_results() functions.
 	 */
-	var $_count_string = "SELECT COUNT(*) AS ";
-	var $_random_keyword;
+	protected $_count_string = 'SELECT COUNT(*) AS ';
+	protected $_random_keyword;
 
 	// need to track the pdo driver and options
-	var $pdodriver;
-	var $options = array();
+	public $pdodriver;
+	public $options = array();
 
-	function __construct($params)
+	public function __construct($params)
 	{
 		parent::__construct($params);
 
@@ -96,19 +94,18 @@
 			$this->_like_escape_str = " ESCAPE '%s' ";
 			$this->_like_escape_chr = '!';
 		}
-		
-		$this->trans_enabled   = FALSE;
+
+		$this->trans_enabled = FALSE;
 		$this->_random_keyword = ' RND('.time().')'; // database specific random keyword
 	}
 
 	/**
 	 * Connection String
 	 *
-	 * @access	private
 	 * @param	array
 	 * @return	void
 	 */
-	function _connect_string($params)
+	protected function _connect_string($params)
 	{
 		if (strpos($this->hostname, ':'))
 		{
@@ -138,7 +135,7 @@
 			$this->dsn = $this->pdodriver.':';
 
 			// Add hostname to the DSN for databases that need it
-			if ( ! empty($this->hostname) 
+			if ( ! empty($this->hostname)
 				&& strpos($this->hostname, ':') === FALSE
 				&& in_array($this->pdodriver, array('informix', 'mysql', 'pgsql', 'sybase', 'mssql', 'dblib', 'cubrid')))
 			{
@@ -153,7 +150,7 @@
 		}
 
 		// Add the database name to the DSN, if needed
-	    if (stripos($this->dsn, 'dbname') === FALSE 
+	    if (stripos($this->dsn, 'dbname') === FALSE
 	       && in_array($this->pdodriver, array('4D', 'pgsql', 'mysql', 'firebird', 'sybase', 'mssql', 'dblib', 'cubrid')))
 	    {
 	        $this->dsn .= 'dbname='.$this->database.';';
@@ -190,10 +187,9 @@
 	/**
 	 * Non-persistent database connection
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @return	object
 	 */
-	function db_connect()
+	public function db_connect()
 	{
 		$this->options[PDO::ATTR_ERRMODE] = PDO::ERRMODE_SILENT;
 
@@ -205,14 +201,13 @@
 	/**
 	 * Persistent database connection
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @return	object
 	 */
-	function db_pconnect()
+	public function db_pconnect()
 	{
-		$this->options[PDO::ATTR_ERRMODE]    = PDO::ERRMODE_SILENT;
+		$this->options[PDO::ATTR_ERRMODE] = PDO::ERRMODE_SILENT;
 		$this->options[PDO::ATTR_PERSISTENT] = TRUE;
-	
+
 		return $this->pdo_connect();
 	}
 
@@ -221,23 +216,22 @@
 	/**
 	 * PDO connection
 	 *
-	 * @access	private called by the PDO driver class
-	 * @return	resource
+	 * @return	object
 	 */
-	function pdo_connect()
+	public function pdo_connect()
 	{
 		// Refer : http://php.net/manual/en/ref.pdo-mysql.connection.php
-		if ($this->pdodriver == 'mysql' && is_php('5.3.6'))
+		if ($this->pdodriver === 'mysql' && ! is_php('5.3.6'))
 		{
 			$this->options[PDO::MYSQL_ATTR_INIT_COMMAND] = "SET NAMES $this->char_set COLLATE '$this->dbcollat'";
 		}
 
 		// Connecting...
-		try 
+		try
 		{
 			$db = new PDO($this->dsn, $this->username, $this->password, $this->options);
-		} 
-		catch (PDOException $e) 
+		}
+		catch (PDOException $e)
 		{
 			if ($this->db_debug && empty($this->failover))
 			{
@@ -258,10 +252,9 @@
 	 * Keep / reestablish the db connection if no queries have been
 	 * sent for a length of time exceeding the server's idle timeout
 	 *
-	 * @access	public
 	 * @return	void
 	 */
-	function reconnect()
+	public function reconnect()
 	{
 		if ($this->db->db_debug)
 		{
@@ -276,10 +269,9 @@
 	/**
 	 * Select the database
 	 *
-	 * @access	private called by the base class
 	 * @return	resource
 	 */
-	function db_select()
+	public function db_select()
 	{
 		// Not needed for PDO
 		return TRUE;
@@ -304,16 +296,15 @@
 	/**
 	 * Execute the query
 	 *
-	 * @access	private called by the base class
 	 * @param	string	an SQL query
-	 * @return	object
+	 * @return	mixed
 	 */
-	function _execute($sql)
+	protected function _execute($sql)
 	{
 		$sql = $this->_prep_query($sql);
 
 		$result_id = $this->conn_id->query($sql);
-		
+
 		if (is_object($result_id))
 		{
 			$this->affect_rows = $result_id->rowCount();
@@ -322,7 +313,7 @@
 		{
 			$this->affect_rows = 0;
 		}
-		
+
 		return $result_id;
 	}
 
@@ -333,11 +324,10 @@
 	 *
 	 * If needed, each database adapter can prep the query string
 	 *
-	 * @access	private called by execute()
 	 * @param	string	an SQL query
 	 * @return	string
 	 */
-	function _prep_query($sql)
+	protected function _prep_query($sql)
 	{
 		if ($this->pdodriver === 'pgsql')
 		{
@@ -358,10 +348,9 @@
 	/**
 	 * Begin Transaction
 	 *
-	 * @access	public
 	 * @return	bool
 	 */
-	function trans_begin($test_mode = FALSE)
+	public function trans_begin($test_mode = FALSE)
 	{
 		if ( ! $this->trans_enabled)
 		{
@@ -387,10 +376,9 @@
 	/**
 	 * Commit Transaction
 	 *
-	 * @access	public
 	 * @return	bool
 	 */
-	function trans_commit()
+	public function trans_commit()
 	{
 		if ( ! $this->trans_enabled)
 		{
@@ -404,7 +392,7 @@
 		}
 
 		$ret = $this->conn->commit();
-		
+
 		return $ret;
 	}
 
@@ -413,10 +401,9 @@
 	/**
 	 * Rollback Transaction
 	 *
-	 * @access	public
 	 * @return	bool
 	 */
-	function trans_rollback()
+	public function trans_rollback()
 	{
 		if ( ! $this->trans_enabled)
 		{
@@ -439,12 +426,11 @@
 	/**
 	 * Escape String
 	 *
-	 * @access	public
 	 * @param	string
 	 * @param	bool	whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
-	function escape_str($str, $like = FALSE)
+	public function escape_str($str, $like = FALSE)
 	{
 		if (is_array($str))
 		{
@@ -455,24 +441,22 @@
 
 			return $str;
 		}
-		
+
 		//Escape the string
 		$str = $this->conn_id->quote($str);
-		
+
 		//If there are duplicated quotes, trim them away
 		if (strpos($str, "'") === 0)
 		{
 			$str = substr($str, 1, -1);
 		}
-		
+
 		// escape LIKE condition wildcards
 		if ($like === TRUE)
 		{
-			$str = str_replace(	array('%', '_', $this->_like_escape_chr),
-								array($this->_like_escape_chr.'%', 
-								      $this->_like_escape_chr.'_', 
-								      $this->_like_escape_chr.$this->_like_escape_chr),
-								$str);
+			return str_replace(array($this->_like_escape_chr, '%', '_'),
+						array($this->_like_escape_chr.$this->_like_escape_chr, $this->_like_escape_chr.'%', $this->_like_escape_chr.'_'),
+						$str);
 		}
 
 		return $str;
@@ -483,10 +467,9 @@
 	/**
 	 * Affected Rows
 	 *
-	 * @access	public
-	 * @return	integer
+	 * @return	int
 	 */
-	function affected_rows()
+	public function affected_rows()
 	{
 		return $this->affect_rows;
 	}
@@ -518,7 +501,6 @@
 	 * Generates a platform-specific query string that counts all records in
 	 * the specified database
 	 *
-	 * @access	public
 	 * @param	string
 	 * @return	string
 	 */
@@ -550,11 +532,10 @@
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @access	private
-	 * @param	boolean
+	 * @param	bool
 	 * @return	string
 	 */
-	function _list_tables($prefix_limit = FALSE)
+	protected function _list_tables($prefix_limit = FALSE)
 	{
 		if ($this->pdodriver == 'pgsql')
 		{
@@ -573,7 +554,7 @@
 
 		if ($prefix_limit !== FALSE AND $this->dbprefix != '')
 		{
-			return FALSE; 
+			return FALSE;
 		}
 
 		return $sql;
@@ -586,11 +567,10 @@
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @access	public
 	 * @param	string	the table name
 	 * @return	string
 	 */
-	function _list_columns($table = '')
+	protected function _list_columns($table = '')
 	{
 		return 'SHOW COLUMNS FROM '.$this->_from_tables($table);
 	}
@@ -602,11 +582,10 @@
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @access	public
 	 * @param	string	the table name
-	 * @return	object
+	 * @return	string
 	 */
-	function _field_data($table)
+	protected function _field_data($table)
 	{
 		if ($this->pdodriver == 'mysql' or $this->pdodriver == 'pgsql')
 		{
@@ -623,7 +602,7 @@
 			// Analog function for sqlite
 			return 'PRAGMA table_info('.$this->_from_tables($table).')';
 		}
-		
+
 		return 'SELECT TOP 1 FROM '.$this->_from_tables($table);
 	}
 
@@ -663,11 +642,10 @@
 	 *
 	 * This function escapes column and table names
 	 *
-	 * @access	private
 	 * @param	string
 	 * @return	string
 	 */
-	function _escape_identifiers($item)
+	public function _escape_identifiers($item)
 	{
 		if ($this->_escape_char == '')
 		{
@@ -707,11 +685,10 @@
 	 * This function implicitly groups FROM tables so there is no confusion
 	 * about operator precedence in harmony with SQL standards
 	 *
-	 * @access	public
-	 * @param	type
-	 * @return	type
+	 * @param	array
+	 * @return	string
 	 */
-	function _from_tables($tables)
+	protected function _from_tables($tables)
 	{
 		if ( ! is_array($tables))
 		{
@@ -728,17 +705,16 @@
 	 *
 	 * Generates a platform-specific insert string from the supplied data
 	 *
-	 * @access	public
 	 * @param	string	the table name
 	 * @param	array	the insert keys
 	 * @param	array	the insert values
 	 * @return	string
 	 */
-	function _insert($table, $keys, $values)
+	protected function _insert($table, $keys, $values)
 	{
 		return 'INSERT INTO '.$this->_from_tables($table).' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
 	}
-	
+
 	// --------------------------------------------------------------------
 
 	/**
@@ -746,13 +722,12 @@
 	 *
 	 * Generates a platform-specific insert string from the supplied data
 	 *
-	 * @access  public
-	 * @param   string  the table name
-	 * @param   array   the insert keys
-	 * @param   array   the insert values
-	 * @return  string
+	 * @param	string	the table name
+	 * @param	array	the insert keys
+	 * @param	array	the insert values
+	 * @return	string
 	 */
-	function _insert_batch($table, $keys, $values)
+	protected function _insert_batch($table, $keys, $values)
 	{
 		return 'INSERT INTO '.$this->_from_tables($table).' ('.implode(', ', $keys).') VALUES '.implode(', ', $values);
 	}
@@ -764,7 +739,6 @@
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @access	public
 	 * @param	string	the table name
 	 * @param	array	the update data
 	 * @param	array	the where clause
@@ -772,7 +746,7 @@
 	 * @param	array	the limit clause
 	 * @return	string
 	 */
-	function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
+	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
 	{
 		foreach ($values as $key => $val)
 		{
@@ -788,7 +762,7 @@
 
 		return $sql;
 	}
-	
+
 	// --------------------------------------------------------------------
 
 	/**
@@ -796,13 +770,12 @@
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @access	public
 	 * @param	string	the table name
 	 * @param	array	the update data
 	 * @param	array	the where clause
 	 * @return	string
 	 */
-	function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index, $where = NULL)
 	{
 		$ids   = array();
 		$where = ($where != '' && count($where) >=1) ? implode(" ", $where).' AND ' : '';
@@ -841,7 +814,6 @@
 		return $sql;
 	}
 
-
 	// --------------------------------------------------------------------
 
 	/**
@@ -851,11 +823,10 @@
 	 * If the database does not support the truncate() command
 	 * This function maps to "DELETE FROM table"
 	 *
-	 * @access	public
 	 * @param	string	the table name
 	 * @return	string
 	 */
-	function _truncate($table)
+	protected function _truncate($table)
 	{
 		return $this->_delete($table);
 	}
@@ -867,13 +838,12 @@
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @access	public
 	 * @param	string	the table name
 	 * @param	array	the where clause
 	 * @param	string	the limit clause
 	 * @return	string
 	 */
-	function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
 	{
 		$conditions = '';
 
@@ -902,13 +872,12 @@
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @access	public
 	 * @param	string	the sql query string
-	 * @param	integer	the number of rows to limit the query to
-	 * @param	integer	the offset value
+	 * @param	int	the number of rows to limit the query to
+	 * @param	int	the offset value
 	 * @return	string
 	 */
-	function _limit($sql, $limit, $offset)
+	protected function _limit($sql, $limit, $offset)
 	{
 		if ($this->pdodriver == 'cubrid' OR $this->pdodriver == 'sqlite')
 		{
@@ -920,7 +889,7 @@
 		{
 			$sql .= 'LIMIT '.$limit;
 			$sql .= ($offset > 0) ? ' OFFSET '.$offset : '';
-			
+
 			return $sql;
 		}
 	}
@@ -930,11 +899,10 @@
 	/**
 	 * Close DB Connection
 	 *
-	 * @access	public
 	 * @param	resource
 	 * @return	void
 	 */
-	function _close($conn_id)
+	protected function _close($conn_id)
 	{
 		$this->conn_id = null;
 	}