So, how can we have an MTI-like structure in the database but without straying too far away from ActiveRecord's well-known realm? The trick is actually quite simple: we continue to use the built-in STI mechanism, but we move the attributes of each child model to a companion ActiveRecord object linked to this model, and we delegate all the attribute accessors to this companion object in order to make it completely transparent for the outside world. The code looks like this:
As Rails validations use the attribute readers (rather than the instance variables), we can keep them in the main class. In addition to simplify the implementation (we don't have to deal with validation errors coming from the companion object), this totally makes sense because the companion object is a mere technicality and not a real business object. After all, what we want to ensure is that a Book has a writer, wherever this writer attribute is actually stored.
ActiveRecord for Real Studio
Rails 6 has added a new feature that adds delegated_type to Active Record. In this blog post, we are going to learn how to use delegated_type in our Active Record model using a real-life project and also discuss the benefits of using it.
This is a guest post by Adrian DeGus. Adrian is the founder of Nuvro, an online project management tool for teams of all sizes. He also runs SEMCentric, a digital marketing agency based out of Phoenix, AZ.Last year I made the decision, like countless others before me, to learn to code as a means to launch a startup. I had been managing web development projects for years which gave me a bit of an advantage, but the road was still far more grueling than I had expected.Within a couple of months, I realized that all the people online claiming to have learned programming in 1-3 months were ei
We simply can't imagine working on a real-world Rails app without having specs. At the same time, we realize that not everyone may yet be comfortable with test-first development. So we have some options for you:
Ah, it has a value of nil! Remember, we fetched the user from the database. Doing that populated all the real (non-virtual) attributes with the values corresponding to each column. But there is no password column, so the password virtual attribute has a value of nil. And that's exactly what we want: there's no trace of the original plain-text password!
We've seen that has_secure_password automatically gives us validations for the presence and confirmation of a user password. That's a really good start, but of course you can add more validations as necessary.
The code is really simple, we get the logger instance ( in this case, from log4net ), check if logging is enabled and if so, write the method and parameters to the log. We then execute the code and log the return value as well.
I just added a new non null property, and all the tests broke. I started to add the new property value to the test, before I realize what I was doing. I run into a friction point, and I was trying to cover it with code. Next time I would add such a property, I would run into the same problem.
I have been waiting on the release for Rhino Mocks 3.5, seeing what kind of feedback I can get from users. I also had another reason, I hadn't had the chance to really give it a good testing, in the only manner that matter, using it to develop production ready software.
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