The short answer is both. There are times when you need to work within the comfort of your own PC without touching the database. On the other hand, sometimes a live connection to a database is exactly what you need.
The most important thing is not whether you choose in-memory or live, but that you have the option to choose.
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Basically, if the question is asked we can pull the data in-memory, build the reports, and then serve them time after time to various users.