[ci skip] DocBlocks for DB drivers' driver classes

Partially fixes issue #1295.

12 files changed, 330 insertions, 167 deletions

diff --git a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
index 70813c479..6ebd92a9b 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
@@ -41,19 +41,28 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = '4d';
 
-	// The character used for escaping
+	/**
+	 * Identifier escape character
+	 *
+	 * @var	string[]
+	 */
 	protected $_escape_char = array('[', ']');
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -81,7 +90,7 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -104,7 +113,7 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -120,7 +129,7 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -135,8 +144,8 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -153,7 +162,7 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -165,11 +174,11 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
index f8e40218e..4f762b91c 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
@@ -41,18 +41,28 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'cubrid';
 
+	/**
+	 * Identifier escape character
+	 *
+	 * @var	string
+	 */
 	protected $_escape_char = '`';
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -76,7 +86,7 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -98,7 +108,7 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -113,7 +123,7 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -128,9 +138,9 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
@@ -169,10 +179,10 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
index 0e1482e55..6ac32fc16 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
@@ -41,18 +41,40 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'dblib';
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
 	protected $_random_keyword = ' NEWID()';
 
+	/**
+	 * Quoted identifier flag
+	 *
+	 * Whether to use SQL-92 standard quoted identifier
+	 * (double quotes) or brackets for identifier escaping.
+	 *
+	 * @var	bool
+	 */
 	protected $_quoted_identifier;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -86,9 +108,9 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Non-persistent database connection
+	 * Database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	object
 	 */
 	public function db_connect($persistent = FALSE)
@@ -116,7 +138,7 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -141,7 +163,7 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -158,8 +180,8 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -176,7 +198,7 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -192,11 +214,11 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
index 5185f738c..83b9648c1 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
@@ -41,21 +41,30 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'firebird';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * 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.
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
 	 */
-	protected $_random_keyword = ' RANDOM()'; // Currently not supported
+	protected $_random_keyword = ' RANDOM()';
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -91,7 +100,7 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -114,7 +123,7 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -129,7 +138,7 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -144,8 +153,8 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
 	 */
 	protected function _update($table, $values)
@@ -161,10 +170,10 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
          */
 	protected function _truncate($table)
@@ -179,7 +188,7 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -191,11 +200,11 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
index e0a4b2855..d8dbc50c0 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
@@ -41,16 +41,21 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'ibm';
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -116,7 +121,7 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -139,7 +144,7 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -155,7 +160,7 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -170,8 +175,8 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -188,7 +193,7 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -200,21 +205,19 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
-	 * @param	int	the number of rows to limit the query to
-	 * @param	int	the offset value
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		$sql .= ' FETCH FIRST '.($limit + $offset).' ROWS ONLY';
+		$sql .= ' FETCH FIRST '.($this->qb_limit + $this->qb_offset).' ROWS ONLY';
 
-		return ($offset)
-			? 'SELECT * FROM ('.$sql.') WHERE rownum > '.$offset
+		return ($this->qb_offset)
+			? 'SELECT * FROM ('.$sql.') WHERE rownum > '.$this->qb_offset
 			: $sql;
 	}
 
diff --git a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
index 45f30ba23..8998670e1 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
@@ -41,16 +41,21 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'informix';
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -109,7 +114,7 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -132,7 +137,7 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -149,7 +154,7 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -164,8 +169,8 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -182,10 +187,10 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -200,7 +205,7 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -212,11 +217,11 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	$SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
index fa8ebfb23..2d076f314 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
@@ -41,19 +41,37 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'mysql';
+
+	/**
+	 * Compression flag
+	 *
+	 * @var	bool
+	 */
 	public $compress = FALSE;
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Identifier escape character
+	 *
+	 * @var	string
+	 */
 	protected $_escape_char = '`';
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -77,9 +95,9 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Non-persistent database connection
+	 * Database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	object
 	 * @todo	SSL support
 	 */
@@ -111,7 +129,7 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -133,7 +151,7 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -148,7 +166,7 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -163,9 +181,9 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	UPDATE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
@@ -204,10 +222,10 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
index 1b4cefb22..2e28476ba 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
@@ -41,24 +41,49 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'oci';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * 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.
+	 * List of reserved identifiers
+	 *
+	 * Identifiers that must NOT be escaped.
+	 *
+	 * @var	string[]
+	 */
+	protected $_reserved_identifiers = array('*', 'rownum');
+
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
 	 */
-	protected $_count_string = 'SELECT COUNT(1) AS ';
 	protected $_random_keyword = ' ASC'; // Currently not supported
 
-	protected $_reserved_identifiers = array('*', 'rownum');
+	/**
+	 * COUNT string
+	 *
+	 * @used-by	CI_DB_driver::count_all()
+	 * @used-by	CI_DB_query_builder::count_all_results()
+	 *
+	 * @var	string
+	 */
+	protected $_count_string = 'SELECT COUNT(1) AS ';
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -98,7 +123,7 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -121,7 +146,7 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -136,7 +161,7 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -149,9 +174,9 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	/**
 	 * Insert_batch statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
 	 * @return 	string
 	 */
 	protected function _insert_batch($table, $keys, $values)
@@ -174,7 +199,7 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -191,11 +216,11 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
index 1b238a4ed..f6e0e215a 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
@@ -41,29 +41,46 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'odbc';
 
-	// The character used for escaping - not used in ODBC
-	protected $_escape_char = '';
+	/**
+	 * Database schema
+	 *
+	 * @var	string
+	 */
+	public $schema = 'public';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " {escape '%s'} ";
+	// --------------------------------------------------------------------
 
-	protected $_random_keyword = ' RAND()';
+	/**
+	 * Identifier escape character
+	 *
+	 * Must be empty for ODBC.
+	 *
+	 * @var	string
+	 */
+	protected $_escape_char = '';
 
 	/**
-	 * Database schema
+	 * ESCAPE statement string
 	 *
 	 * @var	string
 	 */
-	public $schema = 'public';
+	protected $_like_escape_str = " {escape '%s'} ";
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -130,7 +147,7 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool	$prefix_limit = FALSE
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -153,7 +170,7 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -168,8 +185,8 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -186,10 +203,10 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -216,11 +233,11 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
index 2e9430c62..c3f5b7603 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
@@ -41,10 +41,13 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'pgsql';
 
-	protected $_random_keyword = ' RANDOM()';
-
 	/**
 	 * Database schema
 	 *
@@ -52,12 +55,23 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 */
 	public $schema = 'public';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
+	protected $_random_keyword = ' RANDOM()';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -78,7 +92,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	/**
 	 * Insert ID
 	 *
-	 * @param	string
+	 * @param	string	$name
 	 * @return	int
 	 */
 	public function insert_id($name = NULL)
@@ -100,7 +114,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool	$prefix_limit = FALSE
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -124,7 +138,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -139,7 +153,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -154,8 +168,8 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -172,9 +186,9 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
@@ -213,7 +227,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -225,11 +239,11 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlite_driver.php b/system/database/drivers/pdo/subdrivers/pdo_sqlite_driver.php
index 4432b2381..b24b13e76 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlite_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlite_driver.php
@@ -41,21 +41,30 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'sqlite';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * 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.
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
 	 */
-	protected $_random_keyword = ' RANDOM()'; // Currently not supported
+	protected $_random_keyword = ' RANDOM()';
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -82,7 +91,7 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -105,7 +114,7 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -121,7 +130,7 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -134,9 +143,9 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	/**
 	 * Replace statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
 	 * @return 	string
 	 */
 	protected function _replace($table, $keys, $values)
@@ -151,10 +160,10 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
          */
 	protected function _truncate($table)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
index 94c2b9832..b8c60c6b2 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
@@ -41,18 +41,40 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  */
 class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'sqlsrv';
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
 	protected $_random_keyword = ' NEWID()';
 
+	/**
+	 * Quoted identifier flag
+	 *
+	 * Whether to use SQL-92 standard quoted identifier
+	 * (double quotes) or brackets for identifier escaping.
+	 *
+	 * @var	bool
+	 */
 	protected $_quoted_identifier;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -110,9 +132,9 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Non-persistent database connection
+	 * Database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	object
 	 */
 	public function db_connect($persistent = FALSE)
@@ -145,7 +167,7 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -170,7 +192,7 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -187,8 +209,8 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -205,7 +227,7 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -221,11 +243,11 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)