1. A computer-implemented method for querying an opendata provider in communication with a server via an electronic communication network, the method comprising: receiving at the server a relational database query from an application running on a client computer coupled to the electronic communication network; parsing by a parsing engine the relational database query; creating an execution plan based on the results of the parsing step; transmitting an opendata query to the opendata provider, the opendata query including at least a portion of the execution plan; retrieving, at the server, document metadata from the opendata provider; building an internal model of the document metadata; mapping content of at least one opendata entity data model located at the opendata provider and the document metadata to at least one relational model catalog; transforming at the server a response from the opendata provider into a relational format; and providing the transformed response to the client computer application.