1. A method for modeling data, the method comprising: generating for output, by a computing device, a plurality of data item graphical representations, wherein the data item graphical representations represent data items; receiving, by the computing device, one or more inputs to select two or more data items from the data item graphical representations; generating, by the computing device, in response to the one or more inputs, a hierarchical association between the two or more data items, such that the hierarchical association is determined based at least in part on the one or more inputs to select two or more data items; and generating for output, by the computing device, a hierarchical data graphical representation that graphically represents the two or more data items and the hierarchical association between the two or more data items.