[ci skip] DocBlocks for DB drivers' driver classes

Partially fixes issue #1295.
diff --git a/system/database/drivers/ibase/ibase_driver.php b/system/database/drivers/ibase/ibase_driver.php
index 3b5d8f4..fc1c28f 100644
--- a/system/database/drivers/ibase/ibase_driver.php
+++ b/system/database/drivers/ibase/ibase_driver.php
@@ -41,15 +41,30 @@
  */
 class CI_DB_ibase_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'ibase';
 
-	// The character used to escape with
-	protected $_escape_char = '"';
+	// --------------------------------------------------------------------
 
-	protected $_random_keyword = ' Random()'; // database specific random keyword
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
+	protected $_random_keyword = ' Random()';
 
-	// Keeps track of the resource for the current transaction
-	protected $trans;
+	/**
+	 * IBase Transaction status flag
+	 *
+	 * @var	resource
+	 */
+	protected $_ibase_trans;
+
+	// --------------------------------------------------------------------
 
 	/**
 	 * Non-persistent database connection
@@ -104,7 +119,7 @@
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	resource
 	 */
 	protected function _execute($sql)
@@ -117,7 +132,7 @@
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -133,7 +148,7 @@
 		// even if the queries produce a successful result.
 		$this->_trans_failure = ($test_mode === TRUE);
 
-		$this->trans = @ibase_trans($this->conn_id);
+		$this->_ibase_trans = @ibase_trans($this->conn_id);
 
 		return TRUE;
 	}
@@ -153,7 +168,7 @@
 			return TRUE;
 		}
 
-		return @ibase_commit($this->trans);
+		return @ibase_commit($this->_ibase_trans);
 	}
 
 	// --------------------------------------------------------------------
@@ -171,7 +186,7 @@
 			return TRUE;
 		}
 
-		return @ibase_rollback($this->trans);
+		return @ibase_rollback($this->_ibase_trans);
 	}
 
 	// --------------------------------------------------------------------
@@ -179,8 +194,8 @@
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -240,7 +255,7 @@
 	 *
 	 * 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)
@@ -263,7 +278,7 @@
 	 *
 	 * 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 = '')
@@ -278,7 +293,7 @@
 	 *
 	 * 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)
@@ -311,8 +326,8 @@
 	 *
 	 * 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)
@@ -328,10 +343,10 @@
 	 *
 	 * 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)
@@ -346,7 +361,7 @@
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -358,11 +373,11 @@
 	// --------------------------------------------------------------------
 
 	/**
-	 * 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)