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Author's profile photo George McGeachie

A model extension for Entity Inheritance hierarchies in the CDM and LDM

I’ve written a couple of blog posts recently about Entity Inheritance hierarchies, and showed ways in which the customisation features of PowerDesigner are useful when dealing with them. It was triggered partly by the release of PowerDesigner models for FIBO (see, which contain over 400 inheritance hierarchies, some of them 12 levels deep. The model is based on an ontology, hence the deep hierarchies.

I developed a model extension for CDM and LDM to illustrate the points I was making. The core of the extension is a new tab for Entity properties, called Parentage. The tab contains four ‘extended attributes’ and one existing property (the list of parent entities). All of the extended attributes and the list of Parent entities are always complete and up-to-date; the “Ultimate Parents” extended attribute has to be refreshed on demand. There are several different ways to refresh this list, for one entity, for a hierarchy, and for the whole model.

The example shown is an entity in the middle of a pair of hierarchies (note that there are two Ultimate Parents):

Please look at my blog to find out more –

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