Should every table have a Serial id? When would you need one, when wouldnt you? (associations, performance, etc?)
YouTube identifies videos with a key like "ttpYdIodMWc". I want something similar, but can't decide between id and identifier, or just a string key:
property :id, Serial, key: true
property :identifier, String, unique: true
# or
property :id, String, key: true
What is the suggested way for a SQL database, what about for NoSQL?
Some background - making a web app with Sinatra and DataMapper to support a Backbone client app.
