1. A method comprising: receiving, by a database server from a remote application server, a query associated with a calculation scenario that defines a data flow model that includes a plurality of calculation nodes, each calculation node defining one or more operations to execute on the database server, at least one of the nodes being a semantic node specifying an operation requiring special handling, at least one of the nodes being a leaf node having two or more parent nodes, the special handling comprising aggregating of results from the two or more parent nodes without redundant aggregation of results from the at least one leaf node; modifying, by the database server, the query using the semantic node to handle at least one hierarchy view within the calculation scenario, the at least one hierarchy view comprising a calculation model having a plurality of nodes arranged in a hierarchical manner, the plurality of nodes comprising a node having more than one parent node, the modifying the query comprising merging the paths between the semantic node and the at least one leaf node having two or more parent nodes, the merging followed by the aggregating of results from the two or more parent nodes; modifying, by the database server, the calculation scenario based on the modified query; instantiating, by the database server, the modified calculation scenario; executing, by the database server, the operations defined by the calculation nodes of the modified calculation scenario to result in at least one result set; and providing, by the database server to the application server, the at least one result set in response to the query.