1. A method comprising: receiving, by a database server from a remote application server, a query encapsulating an on-the-fly calculation scenario that defines a data flow model that includes one or more calculation nodes, each calculation node defining one or more operations to execute on the database server; instantiating, by the database server, the on-the-fly calculation scenario; executing, by the database server, the operations defined by the calculation nodes of the instantiated calculation scenario to result in a responsive data set; and providing, by the database server to the application server, the data set.