The present disclosure describes methods, systems, and computer program products for providing and maintaining an evolving canonical data model (CDM) which consolidates current knowledge of the correspondences of existing schemas. One computer-implemented method includes receiving the plurality of source hierarchical schemas, each source hierarchical schema being stored as a computer-readable document in computer-readable memory, processing, using a computer, the source hierarchical schemas to generate a merged graph, the merged graph comprising a plurality of merged nodes, each merged node being provided based on one or more nodes from at least two of the source hierarchical schemas, and determining, using the computer, that the merged graph includes one or more conflicts and, in response, resolving each conflict of the one or more conflicts to generate a computed-transitive-edge-free, conflict-free merged graph as a unified data model (UDM), wherein resolving comprises splitting one or more merged nodes into respective sub-sets of merged nodes.