Hi Paul, So partial entities are essentially ORM model "mixins". A neat idea, but unfortunately not supported by Cayenne. So you'd need to recreate the contents of each partial entity insider every concrete entity.
Andrus > On Aug 31, 2024, at 9:51 PM, Paul Hoadley <pa...@logicsquad.net> wrote: > > Hello, > > As part of a review of how we might migrate from EOF → Cayenne, I ran into > our usage of Project Wonder's "partial entities": > > https://jenkins.wocommunity.org/job/Wonder7/lastSuccessfulBuild/javadoc/er/extensions/partials/package-summary.html > > In brief, this feature allows you to have a "base" entity, say "User", which > you might have in a library-style project shared by multiple applications. > Maybe it has attributes like "firstName", "lastName" and "password". Then, at > the application level, you can create a "partial" entity, say "FooUser", on > the "User" base entity. Maybe FooUser has an attribute "isSupervisor", > relevant only to this app. At runtime, the models are merged such that User > is the union of its properties and FooUser's properties, and the underlying > table has all of these columns. The backing classes are distinct, though: in > general, you'd work with Users, but if you need a FooUser, you ask the > relevant User for its FooUser. The win is that you're not re-inventing User > for every new app. It resembles single table inheritance, but FooUser is not > a subclass of User. > > How would I do this in Cayenne? > > > -- > Paul Hoadley > https://logicsquad.net/ > https://www.linkedin.com/company/logic-squad/ >
