Hi,
I am trying to use STI since my classes only vary by one column in the
database.
Here is the structure (names have been changed to protect the innocent):
Case
/ \
Registered Initial
\ /
Children
A registered case has additional information than an initial case (I
realize I could just set a flag to separate them, but there is a good
reason to separate them), but both need to be related to the children
table. Here is the model code:
class Case < ActiveRecord::Base
end
class Registered < Case
has_many :children, :foreign_key => "case_id"
end
class Initial < Case
has_many :children, :foreign_key => "case_id"
end
class Child < ActiveRecord::Base
belongs_to :initial
belongs_to :registered
end
When I attempt to access the children attribute via an Initial object I
get an unknown column exception and the dump shows the sql is trying to
select "initial_id" from the children table. This despite the fact I
specified the foreign key of ''case_id'' in the Initial model.
This has been driving me crazy this evening. All searches for help have
come up empty. Anyone help would be greatly appreciated.
Thanks!
Peer
--
Posted via http://www.ruby-forum.com/.
Hi Peer, With your structure you can add the line has_many :children, :foreign_key => "case_id" to the case definition. The reason that the sql is looking for the initial_id is because the class Child belongs to it. There are 3 options, 1. Include an initial_id and a registered_id to your children table If there is a requirement that it belongs to an inital or registered case only include that in the validation of the child object. 2. Include a case_id in the Child table and change the Child class definition to: class Child < ActiveRecord::Base belongs_to :initial, :foreign_key => ''case_id'' belongs_to :registered, :foreign_key => ''case_id'' end I don''t know the wisdom of doing this one. Having never tried it it may milage may be non-existant. 3. Make Child polymorphic. Then you can associate children with anything. I would tend to go for option 3. It''s cleaner and allows for the future. On 4/7/06, Peer Allan <peer@bipolarsoftware.ca> wrote:> > Hi, > > I am trying to use STI since my classes only vary by one column in the > database. > Here is the structure (names have been changed to protect the innocent): > > > Case > / \ > Registered Initial > \ / > Children > > A registered case has additional information than an initial case (I > realize I could just set a flag to separate them, but there is a good > reason to separate them), but both need to be related to the children > table. Here is the model code: > > class Case < ActiveRecord::Base > end > > class Registered < Case > has_many :children, :foreign_key => "case_id" > end > > > class Initial < Case > has_many :children, :foreign_key => "case_id" > end > > class Child < ActiveRecord::Base > belongs_to :initial > belongs_to :registered > end > > > When I attempt to access the children attribute via an Initial object I > get an unknown column exception and the dump shows the sql is trying to > select "initial_id" from the children table. This despite the fact I > specified the foreign key of ''case_id'' in the Initial model. > > This has been driving me crazy this evening. All searches for help have > come up empty. Anyone help would be greatly appreciated. > > Thanks! > > Peer > > -- > Posted via http://www.ruby-forum.com/. > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060407/f54e7c8f/attachment.html
Sorri to repost so soon, Looking at your associations, you already have the case_id in the child table. With STI initial and registered *ARE* cases. So you can just use the case_id. When you query it you can decide. child.case.type will tell you what class it is. On 4/7/06, Liquid <has.sox@gmail.com> wrote:> > Hi Peer, > > With your structure you can add the line > > has_many :children, :foreign_key => "case_id" > to the case definition. > > The reason that the sql is looking for the initial_id is because the class > Child belongs to it. > > There are 3 options, > > 1. Include an initial_id and a registered_id to your children table > If there is a requirement that it belongs to an inital or registered case > only include that in the validation of the child object. > > 2. Include a case_id in the Child table and change the Child class > definition to: > class Child < ActiveRecord::Base > belongs_to :initial, :foreign_key => ''case_id'' > belongs_to :registered, :foreign_key => ''case_id'' > end > > I don''t know the wisdom of doing this one. Having never tried it it may > milage may be non-existant. > > 3. Make Child polymorphic. Then you can associate children with anything. > > I would tend to go for option 3. It''s cleaner and allows for the future. > > > > > > > > On 4/7/06, Peer Allan <peer@bipolarsoftware.ca> wrote: > > > > Hi, > > > > I am trying to use STI since my classes only vary by one column in the > > database. > > Here is the structure (names have been changed to protect the innocent): > > > > > > Case > > / \ > > Registered Initial > > \ / > > Children > > > > A registered case has additional information than an initial case (I > > realize I could just set a flag to separate them, but there is a good > > reason to separate them), but both need to be related to the children > > table. Here is the model code: > > > > class Case < ActiveRecord::Base > > end > > > > class Registered < Case > > has_many :children, :foreign_key => "case_id" > > end > > > > > > class Initial < Case > > has_many :children, :foreign_key => "case_id" > > end > > > > class Child < ActiveRecord::Base > > belongs_to :initial > > belongs_to :registered > > end > > > > > > When I attempt to access the children attribute via an Initial object I > > get an unknown column exception and the dump shows the sql is trying to > > select "initial_id" from the children table. This despite the fact I > > specified the foreign key of ''case_id'' in the Initial model. > > > > This has been driving me crazy this evening. All searches for help have > > come up empty. Anyone help would be greatly appreciated. > > > > Thanks! > > > > Peer > > > > -- > > Posted via http://www.ruby-forum.com/. > > _______________________________________________ > > Rails mailing list > > Rails@lists.rubyonrails.org > > http://lists.rubyonrails.org/mailman/listinfo/rails > > > >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060407/e3484db8/attachment-0001.html
Daniel ----- wrote:> Sorri to repost so soon, > > Looking at your associations, you already have the case_id in the child > table. > > With STI initial and registered *ARE* cases. So you can just use the > case_id. When you query it you can decide. > > child.case.type will tell you what class it is.This is how I thought it was designed to work and how I thought I had the classes configured to work just like you described here. Am I missing something? Peer -- Posted via http://www.ruby-forum.com/.
Peer Allan wrote:> Daniel ----- wrote: >> Sorri to repost so soon, >> >> Looking at your associations, you already have the case_id in the child >> table. >> >> With STI initial and registered *ARE* cases. So you can just use the >> case_id. When you query it you can decide. >> >> child.case.type will tell you what class it is. > > This is how I thought it was designed to work and how I thought I had > the classes configured to work just like you described here. Am I > missing something? > > PeerI figured out what I was doing wrong and I don''t think I want to mention it in public. But since some nuby (like me) might do the same thing in the future I guess it is only right that I do. When I initially made the system I made separate models for Initial and Registered then I tried to switch it to STI. I know now that I setup up the STI correclty. However, I redeclared my classes, Initial and Registered, in the new case.rb file and did not delete the old model files. Parts of it were working so I thought everything was alright, but I was still using the old models that weren''t configured properly and hence the errors. Once I removed the old files and added the link to the case model in application.rb everything worked just fine. Whoops! Thanks for listening (and helping Daniel!) Peer -- Posted via http://www.ruby-forum.com/.