The OData Protocol is an increasingly powerful RESTful interface for data access. It is in the process of becoming an OASIS Specification.
Definition from the OData site: The Open Data Protocol (OData) is a Web protocol for querying and updating data that provides a way to unlock your data and free it from silos that exist in applications today.OData does this by applying and building upon Web technologies such as HTTP, Atom Publishing Protocol (AtomPub) and JSON to provide access to information from a variety of applications, services, and stores.
Ted Jones has an excellent article, link below, that provides an example of how to expose any datasource as an OData source and then consume the source using OData URLs. His example is shown with Teiid and Teiid Designer which are the community projects for Data Virtualization. Try out his sample code!