Question

I’m working on a new app in Rails 3 but I’m not sure how can I build the relations between the models.

Basically I have a model User and a model Project. An user can create a Project, becoming the project owner. But any other user besides the project owner can join this project as well, but as team member.

Would I need to create a new model for this team relationship? And how would be the relations among this all?

Thanks in advance.

Answer 1

I’m doing something similar with a photo gallery that has shared permissions. Here is roughly the structure I’ve given it (though this is adapted from another project so may not be exactly right).

class User
  has_many :projects, :foreign_key => "owner_id"
  has_many :project_memberships, :foreign_key => "member_id"
  has_many :shared_projects, :class_name => "Project", :through => :project_memberships, :foreign_key => "member_id"
end

class ProjectMembership
  belongs_to :member, :class_name => 'User'
  belongs_to :project
end

class Project
  belongs_to :owner, :class_name => "User"
  has_many :project_memberships
  has_many :members, :class_name => "User", :through => "project_memberships", :foreign_key => "member_id"
end

Basically, this allows a project to have both an owner that’s a user and a bunch of other members that are also users, and they can be accessed separately as such. These are related using a has_many :through relationship, and we’re basically giving a more meaningful name than what the default has_many :users would give us.

This also gives individual members the ability to join a project by creating a new project_membership object for said project, while still maintaining a single owner.