ruby - Validations in Rails

Question

I have designed a very simple web application which associates authors, books and ratings.

In each of the respective models

Author
has_many :books

Book
belongs_to :author
has_many :reviews

Review
belongs_to :book

Model attributes

Author : title, fname, lname, DOB
Book : ISBN,  title, publish_date, pages
Review : rating(1-5), description

I am wondering if I completely validate all of these attributes to my liking in the models, 1 attribute for example

validates :ISBN, :only_integer => true, length: { is: 13 }

do I need to worry about validations for data elsewhere?

I know that validations for the model run on the server side so there may need to be some validation on the client side (in JS). I am trying to ensure that there are no flaws when it comes to asserting data correctness.

question from:https://stackoverflow.com/questions/65643213/validations-in-rails

Answer 1

As is so often the case: it depends.

In a simple Rails application, all models will be updated through a view request to a controller which in turn fills in the params into the models, then tries to save the model and any validation errors that occur are rendered back to the server. In that scenario, all your code will have to do is to react to failed calls to #save but you can sleep soundly knowing that everything in your database is how it is supposed to be.

In more complex applications, putting all the validation logic into your model might not work as well anymore: every call to #save will have to run through all the validation logic, slowing things down, and different parts of your application might have different requirements to the input parameters.

In that scenario there are many ways to go about it. Form objects with validations specific to the forms they represent are a very common solution. These form models then distribute their input among one or more underlying ActiveRecord models.

But the Rails way is to take these one step at a time and avoid premature optimization. For the foreseeable future, putting your validation into your model will be enough to guarantee consistency.