Querying over database columns in Daobab, is extremely easy.
However Projection, which is a wrapper for many columns resulted, might have some issues during JSON conversion.
So, if you want to easily expose your query result directly through REST, and make the data easy to access by frontend, you have to make Projection Flat.
The only thing you have to remember about is to have columns set unique.
FlatProjection, has the same structure as normal Entity. The only difference is that there is no table pointer (since there is no table related).
Also, getters and setters are available in a different way.
Of course, FlatProjection is not an Entity, so cannot have PrimaryKey as well.