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Editorial Team
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Asked: 2026-05-17T17:14:32+00:00

In general, is it better to store raw data with pre-calculated values in the

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In general, is it better to store raw data with pre-calculated values in the database and concentrate on keeping the database up-to-date if I remove or delete a row while using the pre-calculated values for display to the user

OR

is it better to store the raw data and calculate the correct display values on-the-fly?

An example (which is pertinent to my project) would be similar to the following:

You have a timer application. In my case its using Core Data. It’s not connected to the web, but a self-contained app that runs on a computer or mobile device (user’s choice). The app stores a raw start time and a raw end time. The application needs to display the duration of the event and the interval at which the events are occuring. Would it be better to store a pre-calculated “duration” time and even a pre-formatted duration string that will be used for output or would it be better to calculate the duration on-the-fly, so to speak, for display?

Same goes with the interval, although there’s another layer involved because when I create/delete/update a row in the database, I’ll have update the interval for the items that are affected by this. Or, is it better to just calculate as the app executes?

For the record, I’m not trying to micro-optimize. I’m trying to figure out the best way to reduce the amount of code I have to maintain. If performance improves as a result, so be it.

Thoughts?

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1 Answer

  1. Editorial Team

    Generally, you would want to avoid computed values in the DB (from existing columns/tables), unless profiling absolutely dictates that they are necessary (i.e., the DB is underperforming or to great of a load is being placed on the server). This is even more true for formatting of the data, which should almost always be performed on the client side, instead of wasting DB server cycles.

    Of course, any data that is absolutely mandatory to perform the calculations should be stored in the database.

    When you speak of reducing the amount of code you need to maintain, keep in mind that the DBA needs to maintain stored-proc code and table schemas, too. Moving maintenance responsibilities from Developers to DBAs is not eliminating work, it is just shifting it.

    Finally, database changes often cascade to many applications, whereas application changes only affect that application.

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