Added and documented Active Record caching.
Made AR fully database-prefix aware
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index ad747d4..ecd404b 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -433,6 +433,13 @@
 	function _protect_identifiers($item, $affect_spaces = TRUE, $first_word_only = FALSE)

 	{

 		// MSSQL doesn't use backticks

+		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;

+		}

+

 		return $item;

 	}