Added and documented Active Record caching.
Made AR fully database-prefix aware
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index b2e97f9..9e7cc0c 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -448,6 +448,13 @@
 		// we may need "`item1` `item2`" and not "`item1 item2`"

 		if (ctype_alnum($item) === FALSE)

 		{

+			if (strpos($item, '.') !== FALSE)

+			{

+				$aliased_tables = implode(".",$this->ar_aliased_tables).'.';

+				$table_name =  substr($item, 0, strpos($item, '.')+1);

+				$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;

+			}

+

 			// This function may get "field >= 1", and need it to return "`field` >= 1"

 			$lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';