Recently, I was working on an Application when I decided to use bitwise operations on a multi-valued attribute. I haven't done any performance benchmarks, but I would think this should improve the performance on making Queries.
Here's an example: Suppose we want to store Users and their Interests. We should have the following 3 Tables:
- Users - Stores User Information
- Interests - Various Interests
- UserInterests - Stores the Relationship between Users and Interests