Is it possible to have multiple primary keys for one table ?

I want to create table with multiple primary keys. The combination of those keys are unique for each row.

No, but you can use constraints to identify specific columns as unique:

http://support.backendless.com/public/attachments/0bc1ce50bd9331d2cd085eb8f7335cb8.jpg</img>

It looks like we can’t set constraints on the User table. Is there another way to support multiple unique constraints there?