1. Computer apparatus for managing and sharing engineering data for chemical engineering processes and plants, comprising: given one or more software applications of interest and each given application having a respective data model or data view, for each said given application, a class view of the application data model; a composite class view formed by a consolidation of the class views; and a core conceptual data model having a plurality of routes between attributes in the composite view and attributes in the conceptual data model, wherein the class views are effectively one tier, the composite class views are effectively a second tier and the conceptual data model is effectively a third tier, such that a multi-tier data model with links between corresponding attributes across the tiers results, the multi-tier data model enabling management and sharing of engineering data of the given applications with other process and plant engineering applications such that process engineering and plant operations are enhanced.