Ruby on Rails Associations?

If you want to have user. Journals you should write query by hand. As far as I know Rails does has_many :through associations (habtm is a kind of has_many :through ) one level deep.

You can use has_many with finder_sql user.journals. Items in your example doesn't work, becouse journals is an array and it doesn't have items method associated. So, you need to select one journal and then call items : user.journals.first.

Items I would also modify your journals method: def journals self. Roles(:include => :journals). Collect { |role| role.

Journals }.flatten. Uniq end uniq removes duplicates and :inlcude => :journals should improve sql queries.

If you want to have user. Journals you should write query by hand. As far as I know Rails does has_many :through associations (habtm is a kind of has_many :through) one level deep.

You can use has_many with finder_sql. User.journals. Items in your example doesn't work, becouse journals is an array and it doesn't have items method associated.So, you need to select one journal and then call items: user.journals.first.

Items I would also modify your journals method: def journals self. Roles(:include => :journals). Collect { |role| role.

Journals }.flatten. Uniq end uniq removes duplicates and :inlcude => :journals should improve sql queries.

Similar question stackoverflow.com/questions/2802539/ruby... You can use Journal. Scoped to create scope with conditions you need. As you have many-to-many association for journals-roles, you need to access joining table either with separate query or with inner select: def journals Journal.

Scoped(:conditions => "journals. Id in (Select journal_id from journals_roles where role_id in (?))", role_ids) end Then you can use user.journals. All(:include => :items) etc.

Because they make common operations simpler and easier in your code. For example, consider a simple Rails application that includes a model for customers and a model for orders. Each customer can have many orders.

Now, suppose we wanted to add a new order for an existing customer. With Active Record associations, we can streamline these — and other — operations by declaratively telling Rails that there is a connection between the two models. To learn more about the different types of associations, read the next section of this guide.

That’s followed by some tips and tricks for working with associations, and then by a complete reference to the methods and options for associations in Rails. In Rails, an association is a connection between two Active Record models. Associations are implemented using macro-style calls, so that you can declaratively add features to your models.

For example, by declaring that one model belongs_to another, you instruct Rails to maintain Primary Key–Foreign Key information between instances of the two models, and you also get a number of utility methods added to your model. In the remainder of this guide, you’ll learn how to declare and use the various forms of associations. But first, a quick introduction to the situations where each association type is appropriate.

A belongs_to association sets up a one-to-one connection with another model, such that each instance of the declaring model “belongs to” one instance of the other model.

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