Make db_select() clear cached database metadata
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index d40d67a..66d7572 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -158,6 +158,7 @@
 		if (mssql_select_db('['.$database.']', $this->conn_id))
 		{
 			$this->database = $database;
+			$this->data_cache = array();
 			return TRUE;
 		}