Merge changes from develop

25 files changed, 189 insertions, 329 deletions

diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index f848cfe4e..ea56d3819 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -51,6 +51,7 @@ abstract class CI_DB_driver {
 	public $char_set		= 'utf8';
 	public $dbcollat		= 'utf8_general_ci';
 	public $autoinit		= TRUE; // Whether to automatically initialize the DB
+	public $compress		= TRUE;
 	public $swap_pre		= '';
 	public $port			= '';
 	public $pconnect		= FALSE;
@@ -78,6 +79,10 @@ abstract class CI_DB_driver {
 	protected $_protect_identifiers		= TRUE;
 	protected $_reserved_identifiers	= array('*'); // Identifiers that should NOT be escaped
 
+	// clause and character used for LIKE escape sequences
+	protected $_like_escape_str = " ESCAPE '%s' ";
+	protected $_like_escape_chr = '!';
+
 	/**
 	 * The syntax to count rows is slightly different across different
 	 * database engines, so this string appears in each driver and is
@@ -669,7 +674,7 @@ abstract class CI_DB_driver {
 	 */
 	public function is_write_type($sql)
 	{
-		return (bool) preg_match('/^\s*"?(SET|INSERT|UPDATE|DELETE|REPLACE|CREATE|DROP|TRUNCATE|LOAD DATA|COPY|ALTER|RENAME|GRANT|REVOKE|LOCK|UNLOCK|REINDEX)\s+/i', $sql);
+		return (bool) preg_match('/^\s*"?(SET|INSERT|UPDATE|DELETE|REPLACE|CREATE|DROP|TRUNCATE|LOAD|COPY|ALTER|RENAME|GRANT|REVOKE|LOCK|UNLOCK|REINDEX)\s+/i', $sql);
 	}
 
 	// --------------------------------------------------------------------
@@ -1355,7 +1360,7 @@ abstract class CI_DB_driver {
 		}
 		else
 		{
-			$message = ( ! is_array($error)) ? array(str_replace('%s', $swap, $LANG->line($error))) : $error;
+			$message = is_array($error) ? $error : array(str_replace('%s', $swap, $LANG->line($error)));
 		}
 
 		// Find the most likely culprit of the error by going through
@@ -1364,7 +1369,13 @@ abstract class CI_DB_driver {
 		$trace = debug_backtrace();
 		foreach ($trace as $call)
 		{
-			if (isset($call['file']) && strpos($call['file'], BASEPATH.'database') === FALSE)
+			// We'll need this on Windows, as APPPATH and BASEPATH will always use forward slashes
+			if (DIRECTORY_SEPARATOR !== '/')
+			{
+				$call['file'] = str_replace('\\', '/', $call['file']);
+			}
+
+			if (isset($call['file'], $call['class']) && strpos($call['file'], BASEPATH.'database') === FALSE && strpos($call['class'], 'Loader') !== FALSE)
 			{
 				// Found it - use a relative path for safety
 				$message[] = 'Filename: '.str_replace(array(APPPATH, BASEPATH), '', $call['file']);
diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 416132e16..139f467e6 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -1483,19 +1483,18 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
+	 * FROM tables
 	 *
-	 * This public function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
 	 *
-	 * @param       array
-	 * @return      string
+	 * Note: This is only used (and overriden) by MySQL and CUBRID.
+	 *
+	 * @return	string
 	 */
-	protected function _from_tables($tables)
+	protected function _from_tables()
 	{
-		is_array($tables) OR $tables = array($tables);
-
-		return (count($tables) === 1) ? $tables[0] : '('.implode(', ', $tables).')';
+		return implode(', ', $this->qb_from);
 	}
 
 	// --------------------------------------------------------------------
@@ -2010,7 +2009,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 		// Write the "FROM" portion of the query
 		if (count($this->qb_from) > 0)
 		{
-			$sql .= "\nFROM ".$this->_from_tables($this->qb_from);
+			$sql .= "\nFROM ".$this->_from_tables();
 		}
 
 		// Write the "JOIN" portion of the query
diff --git a/system/database/drivers/cubrid/cubrid_driver.php b/system/database/drivers/cubrid/cubrid_driver.php
index e243aae9f..7f8f297bb 100644
--- a/system/database/drivers/cubrid/cubrid_driver.php
+++ b/system/database/drivers/cubrid/cubrid_driver.php
@@ -45,10 +45,6 @@ class CI_DB_cubrid_driver extends CI_DB {
 	// The character used for escaping - no need in CUBRID
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in CUBRID
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '';
-
 	protected $_random_keyword = ' RAND()'; // database specific random keyword
 
 	// CUBRID-specific properties
@@ -72,6 +68,8 @@ class CI_DB_cubrid_driver extends CI_DB {
 		}
 	}
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Non-persistent database connection
 	 *
@@ -431,6 +429,26 @@ class CI_DB_cubrid_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/ibase/ibase_driver.php b/system/database/drivers/ibase/ibase_driver.php
index 7b37b9999..96d6f6526 100644
--- a/system/database/drivers/ibase/ibase_driver.php
+++ b/system/database/drivers/ibase/ibase_driver.php
@@ -45,10 +45,6 @@ class CI_DB_ibase_driver extends CI_DB {
 	// The character used to escape with
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' Random()'; // database specific random keyword
 
 	// Keeps track of the resource for the current transaction
@@ -309,22 +305,6 @@ class CI_DB_ibase_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This public function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index edc6a8480..4369bbefb 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -45,10 +45,6 @@ class CI_DB_mssql_driver extends CI_DB {
 	// The character used for escaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' NEWID()';
 
 	// MSSQL-specific properties
@@ -366,22 +362,6 @@ class CI_DB_mssql_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index 0a15fe447..60bcf3cfc 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -45,10 +45,6 @@ class CI_DB_mysql_driver extends CI_DB {
 	// The character used for escaping
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in MySQL
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '\\';
-
 	protected $_random_keyword = ' RAND()'; // database specific random keyword
 
 	/**
@@ -83,7 +79,14 @@ class CI_DB_mysql_driver extends CI_DB {
 	 */
 	public function db_connect()
 	{
-		return @mysql_connect($this->hostname, $this->username, $this->password, TRUE);
+		if ($this->compress === TRUE)
+		{
+			return @mysql_connect($this->hostname, $this->username, $this->password, TRUE, MYSQL_CLIENT_COMPRESS);
+		}
+		else
+		{
+			return @mysql_connect($this->hostname, $this->username, $this->password, TRUE);
+		}
 	}
 
 	// --------------------------------------------------------------------
@@ -95,7 +98,14 @@ class CI_DB_mysql_driver extends CI_DB {
 	 */
 	public function db_pconnect()
 	{
-		return @mysql_pconnect($this->hostname, $this->username, $this->password);
+		if ($this->compress === TRUE)
+		{
+			return @mysql_pconnect($this->hostname, $this->username, $this->password, MYSQL_CLIENT_COMPRESS);
+		}
+		else
+		{
+			return @mysql_pconnect($this->hostname, $this->username, $this->password);
+		}
 	}
 
 	// --------------------------------------------------------------------
@@ -455,6 +465,26 @@ class CI_DB_mysql_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index 5f5a31d34..934694c6c 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -45,10 +45,6 @@ class CI_DB_mysqli_driver extends CI_DB {
 	// The character used for escaping
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in MySQL
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '\\';
-
 	protected $_random_keyword = ' RAND()'; // database specific random keyword
 
 	/**
@@ -65,6 +61,17 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 */
 	public function db_connect()
 	{
+		// Use MySQL client compression?
+		if ($this->compress === TRUE)
+		{
+			$port = empty($this->port) ? NULL : $this->port;
+
+			$mysqli = new mysqli();
+			@$mysqli->real_connect($this->hostname, $this->username, $this->password, $this->database, $port, NULL, MYSQLI_CLIENT_COMPRESS);
+
+			return $mysqli;
+		}
+
 		return empty($this->port)
 			? @new mysqli($this->hostname, $this->username, $this->password, $this->database)
 			: @new mysqli($this->hostname, $this->username, $this->password, $this->database, $this->port);
@@ -85,6 +92,17 @@ class CI_DB_mysqli_driver extends CI_DB {
 			return $this->db_connect();
 		}
 
+		// Use MySQL client compression?
+		if ($this->compress === TRUE)
+		{
+			$port = empty($this->port) ? NULL : $this->port;
+
+			$mysqli = mysqli_init();
+			$mysqli->real_connect('p:'.$this->hostname, $this->username, $this->password, $this->database, $port, NULL, MYSQLI_CLIENT_COMPRESS);
+
+			return $mysqli;
+		}
+
 		return empty($this->port)
 			? @new mysqli('p:'.$this->hostname, $this->username, $this->password, $this->database)
 			: @new mysqli('p:'.$this->hostname, $this->username, $this->password, $this->database, $this->port);
@@ -400,6 +418,14 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 */
 	public function error()
 	{
+		if ( ! empty($this->conn_id->connect_errno))
+		{
+			return array(
+				'code' => $this->conn_id->connect_errno,
+				'message' => is_php('5.2.9') ? $this->conn_id->connect_error : mysqli_connect_error()
+			);
+		}
+
 		return array('code' => $this->conn_id->errno, 'message' => $this->conn_id->error);
 	}
 
@@ -447,6 +473,26 @@ class CI_DB_mysqli_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/oci8/oci8_driver.php b/system/database/drivers/oci8/oci8_driver.php
index dcc46527c..8e4f4ef9d 100644
--- a/system/database/drivers/oci8/oci8_driver.php
+++ b/system/database/drivers/oci8/oci8_driver.php
@@ -54,10 +54,6 @@ class CI_DB_oci8_driver extends CI_DB {
 	// The character used for excaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	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
@@ -547,22 +543,6 @@ class CI_DB_oci8_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Insert_batch statement
 	 *
 	 * Generates a platform-specific insert string from the supplied data
diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index f62400245..741b7419f 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -45,9 +45,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	// the character used to excape - not necessary for ODBC
 	protected $_escape_char = '';
 
-	// clause and character used for LIKE escape sequences
 	protected $_like_escape_str = " {escape '%s'} ";
-	protected $_like_escape_chr = '!';
 
 	protected $_random_keyword;
 
@@ -291,22 +289,6 @@ class CI_DB_odbc_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index ee5af783e..f4509b17c 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -45,10 +45,6 @@ class CI_DB_pdo_driver extends CI_DB {
 	// The character used to escaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword;
 
 	public $trans_enabled = FALSE;
diff --git a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
index 0e6877c28..438d312a1 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
@@ -130,22 +130,6 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
index 741126310..d2a484d9e 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
@@ -44,10 +44,6 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in CUBRID
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '\\';
-
 	protected $_random_keyword = ' RAND()';
 
 	/**
@@ -183,6 +179,26 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 		return 'TRUNCATE '.$table;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
 }
 
 /* End of file pdo_cubrid_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
index d6465cda2..782bb53c0 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
@@ -153,22 +153,6 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
@@ -239,4 +223,4 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 }
 
 /* End of file pdo_dblib_driver.php */
-/* Location: ./system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php */
\ No newline at end of file
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
index 5b36342d2..32d1f219a 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
@@ -139,22 +139,6 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return 	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
index 7563a42d6..22a5f928c 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
@@ -165,22 +165,6 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
index 82480498a..8dd430184 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
@@ -159,22 +159,6 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
index 67da156bf..9ffb93eed 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
@@ -44,10 +44,6 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in MySQL
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '\\';
-
 	protected $_random_keyword = ' RAND()';
 
 	/**
@@ -211,6 +207,26 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 		return 'TRUNCATE '.$table;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
 }
 
 /* End of file pdo_mysql_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
index cfbb639a8..b03218fad 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
@@ -146,22 +146,6 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Insert_batch statement
 	 *
 	 * @param	string	the table name
diff --git a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
index 0c3467484..5944d55f4 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
@@ -46,7 +46,6 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	protected $_escape_char = '';
 
 	// clause and character used for LIKE escape sequences
-	protected $_like_escape_chr = '!';
 	protected $_like_escape_str = " {escape '%s'} ";
 
 	protected $_random_keyword = ' RAND()';
@@ -157,22 +156,6 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
index 07cf8f56b..74d56e6b8 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
@@ -142,22 +142,6 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
index 4b5747d90..5b1cd9789 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
@@ -182,22 +182,6 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
@@ -273,4 +257,4 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 }
 
 /* End of file pdo_sqlsrv_driver.php */
-/* Location: ./system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php */
\ No newline at end of file
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php */
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index ddcf3f7c3..19f384ccc 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -44,10 +44,6 @@ class CI_DB_postgre_driver extends CI_DB {
 
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' RANDOM()'; // database specific random keyword
 
 	/**
@@ -132,7 +128,15 @@ class CI_DB_postgre_driver extends CI_DB {
 	 */
 	public function db_pconnect()
 	{
-		return @pg_pconnect($this->dsn);
+		$conn = @pg_pconnect($this->dsn);
+		if ($conn && pg_connection_status($conn) === PGSQL_CONNECTION_BAD)
+		{
+			if (pg_ping($conn) === FALSE)
+			{
+				return FALSE;
+			}
+		}
+		return $conn;
 	}
 
 	// --------------------------------------------------------------------
@@ -453,22 +457,6 @@ class CI_DB_postgre_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/sqlite/sqlite_driver.php b/system/database/drivers/sqlite/sqlite_driver.php
index 19824dbbf..2744a63cf 100644
--- a/system/database/drivers/sqlite/sqlite_driver.php
+++ b/system/database/drivers/sqlite/sqlite_driver.php
@@ -45,10 +45,6 @@ class CI_DB_sqlite_driver extends CI_DB {
 	// The character used to escape with - not needed for SQLite
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' Random()'; // database specific random keyword
 
 	/**
diff --git a/system/database/drivers/sqlite3/sqlite3_driver.php b/system/database/drivers/sqlite3/sqlite3_driver.php
index cc35d319f..d03be15f5 100644
--- a/system/database/drivers/sqlite3/sqlite3_driver.php
+++ b/system/database/drivers/sqlite3/sqlite3_driver.php
@@ -46,10 +46,6 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	// The character used for escaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = ' ESCAPE \'%s\' ';
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' RANDOM()';
 
 	/**
@@ -288,25 +284,16 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * The error message string
+	 * Error
 	 *
-	 * @return	string
-	 */
-	protected function _error_message()
-	{
-		return $this->conn_id->lastErrorMsg();
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * The error message number
+	 * Returns an array containing code and message of the last
+	 * database error that has occured.
 	 *
-	 * @return	int
+	 * @return	array
 	 */
-	protected function _error_number()
+	public function error()
 	{
-		return $this->conn_id->lastErrorCode();
+		return array('code' => $this->conn_id->lastErrorCode(), 'message' => $this->conn_id->lastErrorMsg());
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/sqlsrv/sqlsrv_driver.php b/system/database/drivers/sqlsrv/sqlsrv_driver.php
index badbb8e90..659429256 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_driver.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_driver.php
@@ -45,10 +45,6 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	// The character used for escaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' NEWID()';
 
 	// SQLSRV-specific properties
@@ -225,7 +221,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 */
 	public function affected_rows()
 	{
-		return sqlrv_rows_affected($this->result_id);
+		return sqlsrv_rows_affected($this->result_id);
 	}
 
 	// --------------------------------------------------------------------
@@ -362,22 +358,6 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data