Data Aggregation System - a system for information retrieval on demand over relational and non-relational distributed data sources

We present the Data Aggregation System, a system for information retrieval and aggregation from heterogenous sources of relational and non-relational data for the Compact Muon Solenoid experiment on the CERN Large Hadron Collider. The experiment currently has a number of organically-developed data sources, including front-ends to a number of different relational databases and non-database data services which do not share common data structures or APIs {\it (Application Programming Interfaces)}, and cannot at this stage be readily converged. DAS provides a single interface for querying all these services, a caching layer to speed up access to expensive underlying calls and the ability to merge records from different data services pertaining to a single primary key.