Improve the MySQLi database driver

5 files changed, 189 insertions, 354 deletions

diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index 661b42ced..7445a5069 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -257,7 +257,7 @@ class CI_DB_driver {
 
 		// Some DBs have functions that return the version, and don't run special
 		// SQL queries per se. In these instances, just return the result.
-		$driver_version_exceptions = array('oci8', 'sqlite', 'cubrid', 'pdo');
+		$driver_version_exceptions = array('oci8', 'sqlite', 'cubrid', 'pdo', 'mysqli');
 
 		if (in_array($this->dbdriver, $driver_version_exceptions))
 		{
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index aff62a37d..c6ffb4929 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_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 5.1.6 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:
@@ -25,10 +25,8 @@
  * @filesource
  */
 
-// ------------------------------------------------------------------------
-
 /**
- * MySQLi Database Adapter Class - MySQLi only works with PHP 5
+ * MySQLi Database Adapter Class
  *
  * Note: _DB is an extender class that the app controller
  * creates dynamically based on whether the active record
@@ -42,52 +40,40 @@
  */
 class CI_DB_mysqli_driver extends CI_DB {
 
-	var $dbdriver = 'mysqli';
+	public $dbdriver = 'mysqli';
 
 	// The character used for escaping
-	var $_escape_char = '`';
+	protected $_escape_char = '`';
 
 	// clause and character used for LIKE escape sequences - not used in MySQL
-	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 = ' RAND()'; // database specific random keyword
+	protected $_count_string = 'SELECT COUNT(*) AS ';
+	protected $_random_keyword = ' RAND()'; // database specific random keyword
 
 	/**
 	 * Whether to use the MySQL "delete hack" which allows the number
 	 * of affected rows to be shown. Uses a preg_replace when enabled,
 	 * adding a bit more processing to all queries.
 	 */
-	var $delete_hack = TRUE;
-
-	// whether SET NAMES must be used to set the character set
-	var $use_set_names;
-
-	// --------------------------------------------------------------------
+	public $delete_hack = TRUE;
 
 	/**
 	 * Non-persistent database connection
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @return	object
 	 */
-	function db_connect()
+	public function db_connect()
 	{
-		if ($this->port != '')
-		{
-			return @mysqli_connect($this->hostname, $this->username, $this->password, $this->database, $this->port);
-		}
-		else
-		{
-			return @mysqli_connect($this->hostname, $this->username, $this->password, $this->database);
-		}
-
+		return ($this->port != '')
+			? @mysqli_connect($this->hostname, $this->username, $this->password, $this->database, $this->port)
+			: @mysqli_connect($this->hostname, $this->username, $this->password, $this->database);
 	}
 
 	// --------------------------------------------------------------------
@@ -95,12 +81,13 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Persistent database connection
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @return	object
 	 */
-	function db_pconnect()
+	public function db_pconnect()
 	{
-		return $this->db_connect();
+		return ($this->port != '')
+			? @mysqli_connect('p:'.$this->hostname, $this->username, $this->password, $this->database, $this->port)
+			: @mysqli_connect('p:'.$this->hostname, $this->username, $this->password, $this->database);
 	}
 
 	// --------------------------------------------------------------------
@@ -111,10 +98,9 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 * 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 (mysqli_ping($this->conn_id) === FALSE)
 		{
@@ -127,10 +113,9 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Select the database
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @return	bool
 	 */
-	function db_select()
+	public function db_select()
 	{
 		return @mysqli_select_db($this->conn_id, $this->database);
 	}
@@ -140,12 +125,11 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Set client character set
 	 *
-	 * @access	private
 	 * @param	string
 	 * @param	string
-	 * @return	resource
+	 * @return	bool
 	 */
-	function _db_set_charset($charset, $collation)
+	protected function _db_set_charset($charset, $collation)
 	{
 		return function_exists('mysqli_set_charset')
 			? @mysqli_set_charset($this->conn_id, $charset)
@@ -157,12 +141,11 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Version number query string
 	 *
-	 * @access	public
 	 * @return	string
 	 */
-	function _version()
+	protected function _version()
 	{
-		return "SELECT version() AS ver";
+		return @mysqli_get_server_info($this->conn_id);
 	}
 
 	// --------------------------------------------------------------------
@@ -170,15 +153,12 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @access	private called by the base class
 	 * @param	string	an SQL query
-	 * @return	resource
+	 * @return	mixed
 	 */
-	function _execute($sql)
+	protected function _execute($sql)
 	{
-		$sql = $this->_prep_query($sql);
-		$result = @mysqli_query($this->conn_id, $sql);
-		return $result;
+		return @mysqli_query($this->conn_id, $this->_prep_query($sql));
 	}
 
 	// --------------------------------------------------------------------
@@ -188,20 +168,16 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * 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)
 	{
-		// "DELETE FROM TABLE" returns 0 affected rows This hack modifies
-		// the query so that it returns the number of affected rows
-		if ($this->delete_hack === TRUE)
+		// mysqli_affected_rows() returns 0 for "DELETE FROM TABLE" queries. This hack
+		// modifies the query so that it a proper number of affected rows is returned.
+		if ($this->delete_hack === TRUE && preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql))
 		{
-			if (preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql))
-			{
-				$sql = preg_replace("/^\s*DELETE\s+FROM\s+(\S+)\s*$/", "DELETE FROM \\1 WHERE 1=1", $sql);
-			}
+			return preg_replace('/^\s*DELETE\s+FROM\s+(\S+)\s*$/', 'DELETE FROM \\1 WHERE 1=1', $sql);
 		}
 
 		return $sql;
@@ -212,18 +188,12 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @access	public
 	 * @return	bool
 	 */
-	function trans_begin($test_mode = FALSE)
+	public function trans_begin($test_mode = FALSE)
 	{
-		if ( ! $this->trans_enabled)
-		{
-			return TRUE;
-		}
-
 		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}
@@ -231,7 +201,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 		// Reset the transaction failure flag.
 		// If the $test_mode flag is set to TRUE transactions will be rolled back
 		// even if the queries produce a successful result.
-		$this->_trans_failure = ($test_mode === TRUE) ? TRUE : FALSE;
+		$this->_trans_failure = ($test_mode === TRUE);
 
 		$this->simple_query('SET AUTOCOMMIT=0');
 		$this->simple_query('START TRANSACTION'); // can also be BEGIN or BEGIN WORK
@@ -243,18 +213,12 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Commit Transaction
 	 *
-	 * @access	public
 	 * @return	bool
 	 */
-	function trans_commit()
+	public function trans_commit()
 	{
-		if ( ! $this->trans_enabled)
-		{
-			return TRUE;
-		}
-
 		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}
@@ -269,18 +233,12 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Rollback Transaction
 	 *
-	 * @access	public
 	 * @return	bool
 	 */
-	function trans_rollback()
+	public function trans_rollback()
 	{
-		if ( ! $this->trans_enabled)
-		{
-			return TRUE;
-		}
-
 		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}
@@ -295,12 +253,11 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @access	public
 	 * @param	string
 	 * @param	bool	whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
-	function escape_str($str, $like = FALSE)
+	public function escape_str($str, $like = FALSE)
 	{
 		if (is_array($str))
 		{
@@ -312,7 +269,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 			return $str;
 		}
 
-		if (function_exists('mysqli_real_escape_string') AND is_object($this->conn_id))
+		if (function_exists('mysqli_real_escape_string') && is_object($this->conn_id))
 		{
 			$str = mysqli_real_escape_string($this->conn_id, $str);
 		}
@@ -328,7 +285,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 		// escape LIKE condition wildcards
 		if ($like === TRUE)
 		{
-			$str = str_replace(array('%', '_'), array('\\%', '\\_'), $str);
+			return str_replace(array('%', '_'), array('\\%', '\\_'), $str);
 		}
 
 		return $str;
@@ -339,10 +296,9 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Affected Rows
 	 *
-	 * @access	public
-	 * @return	integer
+	 * @return	int
 	 */
-	function affected_rows()
+	public function affected_rows()
 	{
 		return @mysqli_affected_rows($this->conn_id);
 	}
@@ -352,10 +308,9 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Insert ID
 	 *
-	 * @access	public
-	 * @return	integer
+	 * @return	int
 	 */
-	function insert_id()
+	public function insert_id()
 	{
 		return @mysqli_insert_id($this->conn_id);
 	}
@@ -368,27 +323,25 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 * Generates a platform-specific query string that counts all records in
 	 * the specified database
 	 *
-	 * @access	public
 	 * @param	string
 	 * @return	string
 	 */
-	function count_all($table = '')
+	public function count_all($table = '')
 	{
 		if ($table == '')
 		{
 			return 0;
 		}
 
-		$query = $this->query($this->_count_string . $this->_protect_identifiers('numrows') . " FROM " . $this->_protect_identifiers($table, TRUE, NULL, FALSE));
-
+		$query = $this->query($this->_count_string.$this->_protect_identifiers('numrows').' FROM '.$this->_protect_identifiers($table, TRUE, NULL, FALSE));
 		if ($query->num_rows() == 0)
 		{
 			return 0;
 		}
 
-		$row = $query->row();
+		$query = $query->row();
 		$this->_reset_select();
-		return (int) $row->numrows;
+		return (int) $query->numrows;
 	}
 
 	// --------------------------------------------------------------------
@@ -399,16 +352,16 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 * 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)
 	{
-		$sql = "SHOW TABLES FROM ".$this->_escape_char.$this->database.$this->_escape_char;
+		$sql = 'SHOW TABLES FROM '.$this->_escape_char.$this->database.$this->_escape_char;
 
-		if ($prefix_limit !== FALSE AND $this->dbprefix != '')
+		if ($prefix_limit !== FALSE && $this->dbprefix != '')
 		{
-			$sql .= " LIKE '".$this->escape_like_str($this->dbprefix)."%'";
+			return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
 		}
 
 		return $sql;
@@ -421,13 +374,12 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @access	public
 	 * @param	string	the table name
 	 * @return	string
 	 */
-	function _list_columns($table = '')
+	protected function _list_columns($table = '')
 	{
-		return "SHOW COLUMNS FROM ".$this->_protect_identifiers($table, TRUE, NULL, FALSE);
+		return 'SHOW COLUMNS FROM '.$this->_protect_identifiers($table, TRUE, NULL, FALSE);
 	}
 
 	// --------------------------------------------------------------------
@@ -437,13 +389,12 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * 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)
 	{
-		return "DESCRIBE ".$table;
+		return 'DESCRIBE '.$table;
 	}
 
 	// --------------------------------------------------------------------
@@ -451,10 +402,9 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * The error message string
 	 *
-	 * @access	private
 	 * @return	string
 	 */
-	function _error_message()
+	protected function _error_message()
 	{
 		return mysqli_error($this->conn_id);
 	}
@@ -464,10 +414,9 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * The error message number
 	 *
-	 * @access	private
-	 * @return	integer
+	 * @return	int
 	 */
-	function _error_number()
+	protected function _error_number()
 	{
 		return mysqli_errno($this->conn_id);
 	}
@@ -479,11 +428,10 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * This function escapes column and table names
 	 *
-	 * @access	private
 	 * @param	string
 	 * @return	string
 	 */
-	function _escape_identifiers($item)
+	public function _escape_identifiers($item)
 	{
 		if ($this->_escape_char == '')
 		{
@@ -494,24 +442,20 @@ class CI_DB_mysqli_driver extends CI_DB {
 		{
 			if (strpos($item, '.'.$id) !== FALSE)
 			{
-				$str = $this->_escape_char. str_replace('.', $this->_escape_char.'.', $item);
+				$item = str_replace('.', $this->_escape_char.'.', $item);
 
 				// remove duplicates if the user already included the escape
-				return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);
+				return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $this->_escape_char.$item);
 			}
 		}
 
 		if (strpos($item, '.') !== FALSE)
 		{
-			$str = $this->_escape_char.str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item).$this->_escape_char;
-		}
-		else
-		{
-			$str = $this->_escape_char.$item.$this->_escape_char;
+			$item = str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item);
 		}
 
 		// remove duplicates if the user already included the escape
-		return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);
+		return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $this->_escape_char.$item.$this->_escape_char);
 	}
 
 	// --------------------------------------------------------------------
@@ -522,11 +466,10 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 * 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	string
+	 * @return	string
 	 */
-	function _from_tables($tables)
+	protected function _from_tables($tables)
 	{
 		if ( ! is_array($tables))
 		{
@@ -543,15 +486,14 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific insert string from the supplied data
 	 *
-	 * @access	public
 	 * @param	string	the table name
 	 * @param	array	the insert keys
 	 * @param	array	the insert values
 	 * @return	string
 	 */
-	function _insert($table, $keys, $values)
+	protected function _insert($table, $keys, $values)
 	{
-		return "INSERT INTO ".$table." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
+		return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
 	}
 
 	// --------------------------------------------------------------------
@@ -561,15 +503,14 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * 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_batch($table, $keys, $values)
+	protected function _insert_batch($table, $keys, $values)
 	{
-		return "INSERT INTO ".$table." (".implode(', ', $keys).") VALUES ".implode(', ', $values);
+		return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES '.implode(', ', $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -580,17 +521,16 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific replace 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 _replace($table, $keys, $values)
+	protected function _replace($table, $keys, $values)
 	{
-		return "REPLACE INTO ".$table." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
+		return 'REPLACE INTO '.$table.' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
 	}
-	
+
 	// --------------------------------------------------------------------
 
 	/**
@@ -598,7 +538,6 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * 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
@@ -606,24 +545,17 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 * @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)
 		{
-			$valstr[] = $key." = ".$val;
+			$valstr[] = $key.' = '.$val;
 		}
 
-		$limit = ( ! $limit) ? '' : ' LIMIT '.$limit;
-
-		$orderby = (count($orderby) >= 1)?' ORDER BY '.implode(", ", $orderby):'';
-
-		$sql = "UPDATE ".$table." SET ".implode(', ', $valstr);
-
-		$sql .= ($where != '' AND count($where) >=1) ? " WHERE ".implode(" ", $where) : '';
-
-		$sql .= $orderby.$limit;
-
-		return $sql;
+		return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
+			.(($where != '' && count($where) > 0) ? ' WHERE '.implode(' ', $where) : '')
+			.(count($orderby) > 0 ? ' ORDER BY '.implode(', ', $orderby) : '')
+			.( ! $limit ? '' : ' LIMIT '.$limit);
 	}
 
 	// --------------------------------------------------------------------
@@ -633,17 +565,14 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * 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 != '' AND count($where) >=1) ? implode(" ", $where).' AND ' : '';
-
 		foreach ($values as $key => $val)
 		{
 			$ids[] = $val[$index];
@@ -657,25 +586,19 @@ class CI_DB_mysqli_driver extends CI_DB {
 			}
 		}
 
-		$sql = "UPDATE ".$table." SET ";
 		$cases = '';
-
 		foreach ($final as $k => $v)
 		{
-			$cases .= $k.' = CASE '."\n";
-			foreach ($v as $row)
-			{
-				$cases .= $row."\n";
-			}
-
-			$cases .= 'ELSE '.$k.' END, ';
+			$cases .= $k.' = CASE '."\n"
+				.implode("\n", $v)."\n"
+				.'ELSE '.$k.' END, ';
 		}
 
-		$sql .= substr($cases, 0, -2);
-
-		$sql .= ' WHERE '.$where.$index.' IN ('.implode(',', $ids).')';
+		$where = ($where != '' && count($where) > 0) ? implode(' ', $where).' AND ' : '';
 
-		return $sql;
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2)
+			.' WHERE '.(($where != '' && count($where) > 0) ? implode(' ', $where).' AND ' : '')
+			.$index.' IN('.implode(',', $ids).')';
 	}
 
 	// --------------------------------------------------------------------
@@ -687,13 +610,12 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 * 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 "TRUNCATE ".$table;
+		return 'TRUNCATE '.$table;
 	}
 
 	// --------------------------------------------------------------------
@@ -703,31 +625,26 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * 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)
 	{
 		$conditions = '';
-
 		if (count($where) > 0 OR count($like) > 0)
 		{
-			$conditions = "\nWHERE ";
-			$conditions .= implode("\n", $this->ar_where);
+			$conditions = "\nWHERE ".implode("\n", $this->ar_where);
 
 			if (count($where) > 0 && count($like) > 0)
 			{
-				$conditions .= " AND ";
+				$conditions .= ' AND ';
 			}
 			$conditions .= implode("\n", $like);
 		}
 
-		$limit = ( ! $limit) ? '' : ' LIMIT '.$limit;
-
-		return "DELETE FROM ".$table.$conditions.$limit;
+		return 'DELETE FROM '.$table.$conditions.( ! $limit ? '' : ' LIMIT '.$limit);
 	}
 
 	// --------------------------------------------------------------------
@@ -737,22 +654,15 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * 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)
 	{
-		$sql .= "LIMIT ".$limit;
-
-		if ($offset > 0)
-		{
-			$sql .= " OFFSET ".$offset;
-		}
-
-		return $sql;
+		return $sql.' LIMIT '.$limit
+			.($offset > 0 ? ' OFFSET '.$offset : '');
 	}
 
 	// --------------------------------------------------------------------
@@ -760,18 +670,15 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Close DB Connection
 	 *
-	 * @access	public
-	 * @param	resource
+	 * @param	object
 	 * @return	void
 	 */
-	function _close($conn_id)
+	protected function _close($conn_id)
 	{
 		@mysqli_close($conn_id);
 	}
 
-
 }
 
-
 /* End of file mysqli_driver.php */
-/* Location: ./system/database/drivers/mysqli/mysqli_driver.php */
\ No newline at end of file
+/* Location: ./system/database/drivers/mysqli/mysqli_driver.php */
diff --git a/system/database/drivers/mysqli/mysqli_forge.php b/system/database/drivers/mysqli/mysqli_forge.php
index 590efa939..319c6fdac 100644
--- a/system/database/drivers/mysqli/mysqli_forge.php
+++ b/system/database/drivers/mysqli/mysqli_forge.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 5.1.6 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
  */
 
-// ------------------------------------------------------------------------
-
 /**
  * MySQLi Forge Class
  *
@@ -39,13 +37,12 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 	/**
 	 * Create database
 	 *
-	 * @access	private
 	 * @param	string	the database name
-	 * @return	bool
+	 * @return	string
 	 */
-	function _create_database($name)
+	public function _create_database($name)
 	{
-		return "CREATE DATABASE ".$name;
+		return 'CREATE DATABASE '.$name;
 	}
 
 	// --------------------------------------------------------------------
@@ -53,13 +50,12 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 	/**
 	 * Drop database
 	 *
-	 * @access	private
 	 * @param	string	the database name
-	 * @return	bool
+	 * @return	string
 	 */
-	function _drop_database($name)
+	public function _drop_database($name)
 	{
-		return "DROP DATABASE ".$name;
+		return 'DROP DATABASE '.$name;
 	}
 
 	// --------------------------------------------------------------------
@@ -67,68 +63,35 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 	/**
 	 * Process Fields
 	 *
-	 * @access	private
 	 * @param	mixed	the fields
 	 * @return	string
 	 */
-	function _process_fields($fields)
+	private function _process_fields($fields)
 	{
 		$current_field_count = 0;
 		$sql = '';
 
-		foreach ($fields as $field=>$attributes)
+		foreach ($fields as $field => $attributes)
 		{
 			// Numeric field names aren't allowed in databases, so if the key is
 			// numeric, we know it was assigned by PHP and the developer manually
 			// entered the field information, so we'll simply add it to the list
 			if (is_numeric($field))
 			{
-				$sql .= "\n\t$attributes";
+				$sql .= "\n\t".$attributes;
 			}
 			else
 			{
 				$attributes = array_change_key_case($attributes, CASE_UPPER);
 
-				$sql .= "\n\t".$this->db->_protect_identifiers($field);
-
-				if (array_key_exists('NAME', $attributes))
-				{
-					$sql .= ' '.$this->db->_protect_identifiers($attributes['NAME']).' ';
-				}
-
-				if (array_key_exists('TYPE', $attributes))
-				{
-					$sql .=  ' '.$attributes['TYPE'];
-				}
-
-				if (array_key_exists('CONSTRAINT', $attributes))
-				{
-					$sql .= '('.$attributes['CONSTRAINT'].')';
-				}
-
-				if (array_key_exists('UNSIGNED', $attributes) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
-
-				if (array_key_exists('DEFAULT', $attributes))
-				{
-					$sql .= ' DEFAULT \''.$attributes['DEFAULT'].'\'';
-				}
-
-				if (array_key_exists('NULL', $attributes) && $attributes['NULL'] === TRUE)
-				{
-					$sql .= ' NULL';
-				}
-				else
-				{
-					$sql .= ' NOT NULL';
-				}
-
-				if (array_key_exists('AUTO_INCREMENT', $attributes) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
+				$sql .= "\n\t".$this->db->protect_identifiers($field)
+					.( ! empty($attributes['NAME']) ? ' '.$this->db->protect_identifiers($attributes['NAME']).' ' : '')
+					.( ! empty($attributes['TYPE']) ? ' '.$attributes['TYPE'] : '')
+					.( ! empty($attributes['CONSTRAINT']) ? '('.$attributes['CONSTRAINT'].')' : '')
+					.(( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE) ? ' UNSIGNED' : '')
+					.(isset($attributes['DEFAULT']) ? " DEFAULT '".$attributes['DEFAULT']."'" : '')
+					.(( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE) ? ' NULL' : ' NOT NULL')
+					.(( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE) ? ' AUTO_INCREMENT' : '');
 			}
 
 			// don't add a comma on the end of the last field
@@ -146,15 +109,14 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 	/**
 	 * Create Table
 	 *
-	 * @access	private
 	 * @param	string	the table name
 	 * @param	mixed	the fields
 	 * @param	mixed	primary key(s)
 	 * @param	mixed	key(s)
-	 * @param	boolean	should 'IF NOT EXISTS' be added to the SQL
+	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
 	 * @return	bool
 	 */
-	function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	public function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
 	{
 		$sql = 'CREATE TABLE ';
 
@@ -163,15 +125,12 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 			$sql .= 'IF NOT EXISTS ';
 		}
 
-		$sql .= $this->db->_escape_identifiers($table)." (";
-
-		$sql .= $this->_process_fields($fields);
+		$sql .= $this->db->_escape_identifiers($table).' ('.$this->_process_fields($fields);
 
 		if (count($primary_keys) > 0)
 		{
-			$key_name = $this->db->_protect_identifiers(implode('_', $primary_keys));
-			$primary_keys = $this->db->_protect_identifiers($primary_keys);
-			$sql .= ",\n\tPRIMARY KEY ".$key_name." (" . implode(', ', $primary_keys) . ")";
+			$key_name = $this->db->protect_identifiers(implode('_', $primary_keys));
+			$sql .= ",\n\tPRIMARY KEY ".$key_name.' ('.implode(', ', $this->db->protect_identifiers($primary_keys)).')';
 		}
 
 		if (is_array($keys) && count($keys) > 0)
@@ -180,22 +139,20 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 			{
 				if (is_array($key))
 				{
-					$key_name = $this->db->_protect_identifiers(implode('_', $key));
-					$key = $this->db->_protect_identifiers($key);
+					$key_name = $this->db->protect_identifiers(implode('_', $key));
+					$key = $this->db->protect_identifiers($key);
 				}
 				else
 				{
-					$key_name = $this->db->_protect_identifiers($key);
+					$key_name = $this->db->protect_identifiers($key);
 					$key = array($key_name);
 				}
 
-				$sql .= ",\n\tKEY {$key_name} (" . implode(', ', $key) . ")";
+				$sql .= ",\n\tKEY ".$key_name.' ('.implode(', ', $key).')';
 			}
 		}
 
-		$sql .= "\n) DEFAULT CHARACTER SET {$this->db->char_set} COLLATE {$this->db->dbcollat};";
-
-		return $sql;
+		return $sql."\n) DEFAULT CHARACTER SET ".$this->db->char_set.' COLLATE '.$this->db->dbcollat.';';
 	}
 
 	// --------------------------------------------------------------------
@@ -203,12 +160,11 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 	/**
 	 * Drop Table
 	 *
-	 * @access	private
 	 * @return	string
 	 */
-	function _drop_table($table)
+	public function _drop_table($table)
 	{
-		return "DROP TABLE IF EXISTS ".$this->db->_escape_identifiers($table);
+		return 'DROP TABLE IF EXISTS '.$this->db->_escape_identifiers($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -219,31 +175,24 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 	 * Generates a platform-specific query so that a table can be altered
 	 * Called by add_column(), drop_column(), and column_alter(),
 	 *
-	 * @access	private
 	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
 	 * @param	string	the column name
 	 * @param	array	fields
 	 * @param	string	the field after which we should add the new field
-	 * @return	object
+	 * @return	string
 	 */
-	function _alter_table($alter_type, $table, $fields, $after_field = '')
+	public function _alter_table($alter_type, $table, $fields, $after_field = '')
 	{
-		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table)." $alter_type ";
+		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table).' '.$alter_type.' ';
 
 		// DROP has everything it needs now.
-		if ($alter_type == 'DROP')
-		{
-			return $sql.$this->db->_protect_identifiers($fields);
-		}
-
-		$sql .= $this->_process_fields($fields);
-
-		if ($after_field != '')
+		if ($alter_type === 'DROP')
 		{
-			$sql .= ' AFTER ' . $this->db->_protect_identifiers($after_field);
+			return $sql.$this->db->protect_identifiers($fields);
 		}
 
-		return $sql;
+		return $sql.$this->_process_fields($fields)
+			.($after_field != '' ? ' AFTER '.$this->db->protect_identifiers($after_field) : '');
 	}
 
 	// --------------------------------------------------------------------
@@ -253,18 +202,16 @@ class CI_DB_mysqli_forge extends CI_DB_forge {
 	 *
 	 * Generates a platform-specific query so that a table can be renamed
 	 *
-	 * @access	private
 	 * @param	string	the old table name
 	 * @param	string	the new table name
 	 * @return	string
 	 */
-	function _rename_table($table_name, $new_table_name)
+	public function _rename_table($table_name, $new_table_name)
 	{
-		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table_name)." RENAME TO ".$this->db->_protect_identifiers($new_table_name);
-		return $sql;
+		return 'ALTER TABLE '.$this->db->protect_identifiers($table_name).' RENAME TO '.$this->db->protect_identifiers($new_table_name);
 	}
 
 }
 
 /* End of file mysqli_forge.php */
-/* Location: ./system/database/drivers/mysqli/mysqli_forge.php */
\ No newline at end of file
+/* Location: ./system/database/drivers/mysqli/mysqli_forge.php */
diff --git a/system/database/drivers/mysqli/mysqli_result.php b/system/database/drivers/mysqli/mysqli_result.php
index 89dd4ded8..0a50cccac 100644
--- a/system/database/drivers/mysqli/mysqli_result.php
+++ b/system/database/drivers/mysqli/mysqli_result.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 5.1.6 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
  */
 
-// ------------------------------------------------------------------------
-
 /**
  * MySQLi Result Class
  *
@@ -41,10 +39,9 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	/**
 	 * Number of rows in the result set
 	 *
-	 * @access	public
-	 * @return	integer
+	 * @return	int
 	 */
-	function num_rows()
+	public function num_rows()
 	{
 		return @mysqli_num_rows($this->result_id);
 	}
@@ -54,10 +51,9 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	/**
 	 * Number of fields in the result set
 	 *
-	 * @access	public
-	 * @return	integer
+	 * @return	int
 	 */
-	function num_fields()
+	public function num_fields()
 	{
 		return @mysqli_num_fields($this->result_id);
 	}
@@ -69,10 +65,9 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	 *
 	 * Generates an array of column names
 	 *
-	 * @access	public
 	 * @return	array
 	 */
-	function list_fields()
+	public function list_fields()
 	{
 		$field_names = array();
 		while ($field = mysqli_fetch_field($this->result_id))
@@ -90,40 +85,36 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	 *
 	 * Generates an array of objects containing field meta-data
 	 *
-	 * @access	public
 	 * @return	array
 	 */
-	function field_data()
+	public function field_data()
 	{
 		$retval = array();
 		while ($field = mysqli_fetch_object($this->result_id))
 		{
 			preg_match('/([a-zA-Z]+)(\(\d+\))?/', $field->Type, $matches);
 
-			$type = (array_key_exists(1, $matches)) ? $matches[1] : NULL;
-			$length = (array_key_exists(2, $matches)) ? preg_replace('/[^\d]/', '', $matches[2]) : NULL;
-
-			$F				= new stdClass();
-			$F->name		= $field->Field;
-			$F->type		= $type;
-			$F->default		= $field->Default;
-			$F->max_length	= $length;
-			$F->primary_key = ( $field->Key == 'PRI' ? 1 : 0 );
+			$F		= new stdClass();
+			$F->name	= $field->Field;
+			$F->type	= ( ! empty($matches[1])) ? $matches[1] : NULL;
+			$F->default	= $field->Default;
+			$F->max_length	= ( ! empty($matches[2])) ? preg_replace('/[^\d]/', '', $matches[2]) : NULL;
+			$F->primary_key = (int) ($field->Key === 'PRI');
 
 			$retval[] = $F;
 		}
 
 		return $retval;
 	}
-	
+
 	// --------------------------------------------------------------------
 
 	/**
 	 * Free the result
 	 *
-	 * @return	null
+	 * @return	void
 	 */
-	function free_result()
+	public function free_result()
 	{
 		if (is_object($this->result_id))
 		{
@@ -141,10 +132,9 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	 * this internally before fetching results to make sure the
 	 * result set starts at zero
 	 *
-	 * @access	private
 	 * @return	array
 	 */
-	function _data_seek($n = 0)
+	protected function _data_seek($n = 0)
 	{
 		return mysqli_data_seek($this->result_id, $n);
 	}
@@ -156,10 +146,9 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an array
 	 *
-	 * @access	private
 	 * @return	array
 	 */
-	function _fetch_assoc()
+	protected function _fetch_assoc()
 	{
 		return mysqli_fetch_assoc($this->result_id);
 	}
@@ -171,16 +160,14 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @access	private
 	 * @return	object
 	 */
-	function _fetch_object()
+	protected function _fetch_object()
 	{
 		return mysqli_fetch_object($this->result_id);
 	}
 
 }
 
-
 /* End of file mysqli_result.php */
-/* Location: ./system/database/drivers/mysqli/mysqli_result.php */
\ No newline at end of file
+/* Location: ./system/database/drivers/mysqli/mysqli_result.php */
diff --git a/system/database/drivers/mysqli/mysqli_utility.php b/system/database/drivers/mysqli/mysqli_utility.php
index 76bd49e31..3fdc5c723 100644
--- a/system/database/drivers/mysqli/mysqli_utility.php
+++ b/system/database/drivers/mysqli/mysqli_utility.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 5.1.6 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
  */
 
-// ------------------------------------------------------------------------
-
 /**
  * MySQLi Utility Class
  *
@@ -39,12 +37,11 @@ class CI_DB_mysqli_utility extends CI_DB_utility {
 	/**
 	 * List databases
 	 *
-	 * @access	private
-	 * @return	bool
+	 * @return	string
 	 */
-	function _list_databases()
+	public function _list_databases()
 	{
-		return "SHOW DATABASES";
+		return 'SHOW DATABASES';
 	}
 
 	// --------------------------------------------------------------------
@@ -54,13 +51,12 @@ class CI_DB_mysqli_utility extends CI_DB_utility {
 	 *
 	 * Generates a platform-specific query so that a table can be optimized
 	 *
-	 * @access	private
 	 * @param	string	the table name
-	 * @return	object
+	 * @return	string
 	 */
-	function _optimize_table($table)
+	public function _optimize_table($table)
 	{
-		return "OPTIMIZE TABLE ".$this->db->_escape_identifiers($table);
+		return 'OPTIMIZE TABLE '.$this->db->_escape_identifiers($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -70,13 +66,12 @@ class CI_DB_mysqli_utility extends CI_DB_utility {
 	 *
 	 * Generates a platform-specific query so that a table can be repaired
 	 *
-	 * @access	private
 	 * @param	string	the table name
-	 * @return	object
+	 * @return	string
 	 */
-	function _repair_table($table)
+	public function _repair_table($table)
 	{
-		return "REPAIR TABLE ".$this->db->_escape_identifiers($table);
+		return 'REPAIR TABLE '.$this->db->_escape_identifiers($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -84,11 +79,10 @@ class CI_DB_mysqli_utility extends CI_DB_utility {
 	/**
 	 * MySQLi Export
 	 *
-	 * @access	private
 	 * @param	array	Preferences
 	 * @return	mixed
 	 */
-	function _backup($params = array())
+	public function _backup($params = array())
 	{
 		// Currently unsupported
 		return $this->db->display_error('db_unsuported_feature');
@@ -96,4 +90,4 @@ class CI_DB_mysqli_utility extends CI_DB_utility {
 }
 
 /* End of file mysqli_utility.php */
-/* Location: ./system/database/drivers/mysqli/mysqli_utility.php */
\ No newline at end of file
+/* Location: ./system/database/drivers/mysqli/mysqli_utility.php */