The Portland Common Data Model (P·C·D·M) is a set of vocabularies published by Duraspace and used by certain institutions and communities in the library and cultural heritage sphere for modelling their collections. It comprises five parts :⁠—

P·C·D·M Models builds on top of to provide basic structural modelling for Collections, their Objects, and the Files associated with them. This ontology only omits the term , whose meaning and utility is unclear.

P·C·D·M Use provides subclasses for which identify its intended use. The choice of modelling this using classes, rather than a relationship like , is a bit suspect, but a conversion from one to the other is not especially difficult.

P·C·D·M Rights provides a few terms for specifying temporary, time‐limited overrides to rights statements. As this is use·case is fairly domain‐specific and niche, this ontology does not bother defining its terms.

P·C·D·M Works expands P·C·D·M Models to add the concepts of Work and File Set. It also defines two classes for use with , and , which are more suspect in utility and not included in this ontology.

P·C·D·M File Formats provides a set of Concepts for denoting specific file format genres. These are a bit undocumented, and don¦t have a clear use·case, so they not been encoded into this ontology.