I'm currently rewriting a python GAE app in Java, and am question my entity design. I have entities like the following so that I could query the datastore and easily get back a unique list of designers:
class Designer
class Jean
The code would be much simpler if I get rid of the Designer class since all it does is wrap a String, but I can't do a SELECT DISTINCT Designer FROM Jean to get a list of Jean designers. Is the first approach the correct one, or is there another way?
GAE(datastore-bigtable) doesn't support the complex query like SQL, So then you'll have to design your own model(db) structure like as you explained earlier.