It’s not that MySQL and other DBs sort things on their own, it’s that they don’t sort them. When you call Model.find([5, 2, 3]), the SQL generated is something like: SELECT * FROM models WHERE models.id IN (5, 2, 3) This doesn’t specify an order, just the set of records you want returned. It turns … Read more
Rails 4+ ActiveRecord 4.0 and above adds where.not so you can do this: Foo.includes(:bar).where.not(‘bars.id’ => nil) Foo.includes(:bar).where.not(bars: { id: nil }) When working with scopes between tables, I prefer to leverage merge so that I can use existing scopes more easily. Foo.includes(:bar).merge(Bar.where.not(id: nil)) Also, since includes does not always choose a join strategy, you should … Read more
The ability to chain or clause along with where clause in ActiveRecord query will be available in Rails 5. See the related discussion and the pull request. So, you will be able to do the following things in Rails 5: To get a post with id 1 or 2: Post.where(‘id = 1’).or(Post.where(‘id = 2’)) Some … Read more
I’d say your instincts to keep current_user out of the model are correct. Like Daniel I’m all for skinny controllers and fat models, but there is also a clear division of responsibilities. The purpose of the controller is to manage the incoming request and session. The model should be able to answer the question “Can … Read more
If you want to combine using AND (intersection), use merge: first_name_relation.merge(last_name_relation) If you want to combine using OR (union), use or†: first_name_relation.or(last_name_relation) † Only in ActiveRecord 5+; for 4.2 install the where-or backport.
You would do Person.where(‘name=? OR lastname=?’, ‘John’, ‘Smith’) Right now, there isn’t any other OR support by the new AR3 syntax (that is without using some 3rd party gem).
There are 5 options that could be considered as implementations of «Hash notation» (the last two are kinda hash-ish): With Ruby on Rails 5 you are able to do the following chaining using ActiveRecord::Relation#or method: Person.where(name: ‘Neil’).or(Person.where(age: 27)) Use where_values together with reduce. The unscoped method is necessary only for Rails 4.1+ to ensure default_scope … Read more
Sometimes, you want to use different names for different associations. If the name you want to use for an association on the model isn’t the same as the assocation on the :through model, you can use :source to specify it. I don’t think the above paragraph is much clearer than the one in the docs, … Read more
Here are all the Rails 4 (ActiveRecord migration) datatypes: :binary :boolean :date :datetime :decimal :float :integer :bigint :primary_key :references :string :text :time :timestamp Source: http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-add_column These are the same as with Rails 3. If you use PostgreSQL, you can also take advantage of these: :hstore :json :jsonb :array :cidr_address :ip_address :mac_address They are stored as … Read more
Use update_column (Rails >= v3.1) or update_columns (Rails >= 4.0) to skip callbacks and validations. Also with these methods, updated_at is not updated. #Rails >= v3.1 only @person.update_column(:some_attribute, ‘value’) #Rails >= v4.0 only @person.update_columns(attributes) http://api.rubyonrails.org/classes/ActiveRecord/Persistence.html#method-i-update_column #2: Skipping callbacks that also works while creating an object class Person < ActiveRecord::Base attr_accessor :skip_some_callbacks before_validation :do_something after_validation :do_something_else … Read more