 A big step towards the modern modelling languages is found in UIMP
, where the structure of the mathematical programming models taken from real life is analysed for the first time, to highlight the natural grouping of variables and constraints arising from such models.This led to data-structure features, which supported structured modelling; in this paradigm, all the input and output tables, together with the decision variables, are defined in terms of these structures, in a way comparable to the use of subscripts and sets.This is probably the single most notable feature common to all modern AMLs and enabled, in time, a separation between the model structure and its data, and a correspondence between the entities in an MP model and data in relational databases.