Guys,
Good stuff.
@Walter - what bothers me about the Role approach is that I will need
to write accessor methods on Project -- #primary_record_owner,
#record_owners -- to retrieve the desired Role players by finding on
attributes like is_record_owner or is_primary_record_owner in Role.
That's not too great a burden, but...
@Jim - maybe I can get what I need from something along the lines of
the following?
class Project < ActiveRecord::Base
has_one :primary_record_owner ... # see discussion farther below...
has_and_belongs_to_many :record_owners, :class_name =>
"User", :join_table => :projects_record_owners
has_and_belongs_to_many :users, :join_table => :projects_users
end
class User < ActiveRecord::Base
has_many :projects, :include =>
[:record_owners, :users, :primary_record_owner], :include =>
'primary_record_owner = #{self.id} OR record_owners.user_id =
#{self.id} OR project_users.user_id = #{self.id}'
end
I'm in over head...I think this dead-ends in at least one place, with
the has_one association in Project. Seems like I would have to
describe that as a has_one :through association.
Lille
On Feb 14, 11:50 am, Jim Ruther Nill <[email protected]> wrote:
> On Mon, Feb 14, 2011 at 11:04 PM, Walter Lee Davis <[email protected]>wrote:
>
>
>
>
>
> > On Feb 14, 2011, at 9:53 AM, Lille wrote:
>
> > Jim,
>
> >> Thanks, but your proposed RecordOwner would have no behavior distinct
> >> from User and would not describe the relationship from the Project
> >> model's perspective. My User shouldn't care about the kind of relation
> >> it has to Project, rather the reverse.
>
> >> My pseudocode is about as specific as I know how to get.
>
> >> To recap in its most distilled form, my problem is what relationships
> >> to include in two models, User and Project, where a User may be
> >> associated with Project in any of three ways -- User,
> >> 'primary_record_owner', or 'record_owner, such that the following
> >> expressions are possible:
>
> >> 1) @user.projects # returns all projects associated with a User
> >> instance
>
> Can't you use a condition for the has many while eager loading the other
> models? Something like
>
> has_many :projects, :include => [:record_owners, :project_users], :include
> => 'primary_record_owner = #{self.id} OR record_owners.user_id = #{self.id}
> OR project_users.user_id = #{self.id}'
>
>
>
> > 2) @project.primary_record_owner # returns a User instance
> >> 3) @project.record_owners # returns a collection of User instances
> >> 4) @project.users # returns a collection of User instances
>
> >> I think I see how to accomplish 2-4, using HABTM, but I don't see how
> >> to accomplish 1) at the same time.
>
> > Have you thought about a polymorphic join model between the two, like maybe
> > a Role? That's how I ended up structuring a recent project.
>
> > Walter
>
> >> Thanks,
>
> >> Lille
>
> >> On Feb 13, 8:41 pm, Jim Ruther Nill <[email protected]> wrote:
>
> >>> I'm thinking about 4 models
>
> >>> - User
> >>> - Project
> >>> - RecordOwner
> >>> - UserProject -> this is the join table for user and project
>
> >>> You won't need RecordOwner if record_owners is a subset of the users
> >>> association.
> >>> Give us an example so we can help out with the options you want.
>
> >>> On Mon, Feb 14, 2011 at 8:17 AM, Lille <[email protected]> wrote:
>
> >>>> Hi,
>
> >>> I want to specify relationships between two classes like that
> >>>> expressed in the following pseudocode:
>
> >>> class User < ActiveRecord::Base
> >>>> has_many :projects
> >>>> end
>
> >>> class Project < ActiveRecord::Base
>
> >>> has_one :primary_record_owner, :<pseudo_option_for_referring_to>=>"User"
> >>>> has_many :record_owners, :<pseudo_option_for_referring_to>=>"User"
> >>>> has_many :users # this refers to User, too
> >>>> end
>
> >>> From the above I seek the following kind of results:
>
> >>> @user.projects # returns all projects associated with the user from
> >>>> any of the three User associations in Project
> >>>> @project.primary_record_owner # returns the User instance
> >>>> @project.record_owners # returns the collection of User instances
> >>>> @project.users # returns User instances, not necessarily overlapping
> >>>> with the other associations
>
> >>> The intent I mean to express is that a Project can have any of three
> >>>> levels of relationship with a User, while a User has only one level of
> >>>> association with a Project.
>
> >>> I was thinking HABTM, but I don't see how to get my desired
> >>>> '[email protected]' result from that.
>
> >>> Any helpful comment would be greatly appreciated.
>
> >>> Thanks,
>
> >>> Lille
>
> >>> --
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>
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