CODEWITHSUNDEEP
ruby-on-railsmodel-view-controller
Jon Girard
Jon Girard

Reputation: 247

Identifying where to put controller versus model logic

I'm trying to figure out the best (or rather the most practical/efficient) way of doing something in my rails application. Basically what I have is an area where a user must enter some information in several form fields which I currently have DB columns for (income for example).

With that information obtained from the user, some calculations need to be performed (say, for example: income and rrsp contribution need to be run through a simple formula to determine the approximate taxable income of the user).

My question is, would it be best practice to perform said calculation in a method at the model level, and save that processed information in a DB column of its own, or would I perform said calculations of the raw input data at a controller level, requiring processing each time?

I'm guessing it's probably generally best to store the calculated data in the database so it doesn't need to be processed each time, but I'm basically looking for best practices to follow in this case and in general. It probably also depends widely based on the applications specific requirements I'd guess.

Upvotes: 0

Views: 35

Answers (1)

ben author
ben author

Reputation: 2955

My preference is to store raw (or lightly sanitized) data only. Then turn the formulae you need into methods on your model, or perhaps library/helper functions, depending on the structure of your project as a whole.

When you start storing processed data, you need to start worrying about the task of syncing when the source data changes. This can be messy and hard.

Since computers are fast at arithmetic, and for a web application relying on a database the arithmetic is not likely to be your performance bottleneck, i wouldn't worry about the performance overhead. If it became a bottleneck, i might start to think about a cache layer.

Upvotes: 1

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