This works well to fetch 100,000 contacts in a list and only draw the ones visible to the user as they scroll. What works less well is the common use case of a list view where you might only want to show several attributes of a large record.
So a list of contacts might show just:
To fetch this data requires a query on contact with a prefetch to invoices. Lots of data being loaded from two or more tables and potentially a bit slow.
1. Use DataRows. This is simple, but you lose some of the nice modelling/entity features from Cayenne. You have to type all the columns yourself.
2. Create a view in the database with just three columns (plus a PK) and create a separate read-only Cayenne model which maps to that view. But now you are hardcoding your application to a specific database and changing the representation is hard.
I want something half way between the two. SQLtemplate to fetch only the columns or aggregates I need, but mapped to some sort of read-only lightweight Cayenne entity.
Has anyone tried something like this?
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