The CMS experiment has implemented a flexible and powerful approach to enable users to find data within the CMS physics data catalog. The Dataset Bookkeeping Service (DBS) comprises a database and the services used to store and access metadata related to its physics data. In addition to the existing WEB based and programatic API, a generalized query system has been designed and built. This query system has a query language that hides the complexity of the underlying database structure. This provides a way of querring the system that is straightforward for CMS data managers and physicists. We will describe the design of the query system and provide details of the language components. We will also provide an overview of how this component fits into the overall data discovery, and bookkeeping systems for CMS.