I would argue if you don't know how your data is going to be used then you should use the most flexible option - a normalised relational database. This gives y

I would argue if you don't know how your data is going to be used then you should use the most flexible option - a normalised relational database. This gives you the most flexibility when querying, whereas with a denormalised database you need to know how you're going to query it ahead of time. Unless you want to abandon any semblance of performance.