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So in Rails 4 the long desired feature to use not queries has been added.
Article.where.not(title: 'Rails 3') Has similar support been added for or queries, or are they planning to make it. I couldn't find anything by browsing through the release notes.
Obviously I tried
Article.where(title: 'Rails 3').or(title: 'Rails 4') But that does not work.
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Eager loading lets you preload the associated data (authors) for all the posts from the database, improves the overall performance by reducing the number of queries, and provides you with the data that you want to display in your views, but the only catch here is which one to use.
Active Record is the M in MVC - the model - which is the layer of the system responsible for representing business data and logic. Active Record facilitates the creation and use of business objects whose data requires persistent storage to a database.
The Relation Class. Having queries return an ActiveRecord::Relation object allows us to chain queries together and this Relation class is at the heart of the new query syntax. Let's take a look at this class by searching through the ActiveRecord source code for a file called relation.
Article.where(title: ['Rails 3', 'Rails 4']) is how you'd do that in Active Record.
It's not possible to replicate any arbitrary SQL query using "Rails-y" syntax. But you can always just pass in literal sql.
So you could also do:
Article.where("articles.title = 'Rails 3' OR articles.title = 'Rails 4'") This now works in Rails 5:
Article.where(title: 'Rails 3').or(Article.where(title: 'Rails 4')) Code example in Rails's source.
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