1
vote
1answer
421 views

ORDER BY on aggregate field on a closure table giving unexpected results

I am updating my companies product database and I'm looking into different ways to do design our faceted navigation "selector" tables. The idea of faceted navigation might look like this: It's ...
23
votes
7answers
7k views

Writing a simple bank schema: How should I keep my balances in sync with their transaction history?

I am writing the schema for a simple bank database. Here are the basic specifications: The database will store transactions against a user and currency. Every user has one balance per currency, so ...
40
votes
4answers
3k views

Storing vs calculating aggregate values

Are there any guidelines or rules of thumb to determine when to store aggregate values and when to calculate them on the fly? For example, suppose I have widgets which users can rate (see schema ...