7. A method for accessing data in an information source, the method comprising: storing, in a plurality of disparate information sources, different types of data each defined by a set of physical metadata elements; storing, in a metadata repository, two sets of metadata elements, wherein a first set of the metadata elements comprises the sets of physical metadata elements defining the plurality of disparate information sources, and wherein the second set of metadata elements includes logical metadata elements that are linked to one or more of the physical metadata elements of the first set of metadata elements; receiving, at a server coupled to the metadata repository and to the plurality of information sources, a query request in a single query request language for one or more of the logical metadata elements from a user via application programming interface (API); converting, by the server using a microprocessor, the query request to a source-specific data query request corresponding to one or more of the disparate information sources by referencing the two sets of metadata elements in the metadata repository; generate, by the server using a microprocessor upon receiving the query request, a query plan for retrieving data from the one or more of the disparate information sources referenced by the source-specific data query request, wherein the query plan operates asynchronously to retrieve the data by performing a first query operation and then performing a second query operation prior to receiving the results of the first query operation; retrieving, by the server, data directly from the one or more disparate information sources referenced by the source-specific data query request in real time; and integrating, by the server, the retrieved data into a global response to the query request to be returned to the user; wherein the second set of metadata elements in the metadata repository further includes a transformational logical metadata element that is linked to a transformational logical rule element that transforms, using a microprocessor, the data retrieved at the transformational logical metadata element into different data by applying a mathematical operation to the retrieved data including at least one of multiplication, division, addition, and subtraction.
9. The method according to claim 7 , wherein the query plan for retrieving the data from the one or more disparate information sources optimizes the processing of the query request.