a data model representing a multi - model database of a product system includes a multi - model repository that holds said multi - model database &# 39 ; s artifacts under version control . the multi - model repository holds a plurality of constituent models , wherein each model represents a discrete aspect of the system , a model registry containing a list of the constituent models in the multi - model database , a set of input attributes and a set of output attributes corresponding to each of the models , a set of interfaces representing a tuple corresponding to each of the models , a set of attribute constraints associated with the input and output attributes ; and a set of notifications associated with each of the models for informing the models of defined events .