Has_many and belons_to Problem

Rails
1

Dear all,

I have a problem with the relations of a model. The problem is the
following.

I have 2 models. Page and PeContainer.
Page:
has_and_belongs_to_many :pe_containers

PeContainer
belongs_to :page
has_many :pages

Page
---->PeContainer
-------->Page
------------>PeContainer

So my mainproblem is to get the parentpage of the PeContainer. I can
only access the childpages. Can anyone help? Thanks in advance!

Kind regards
Alex

2

On 4/10/07, physalias [email protected] wrote:

------------>PeContainer
Hmm, that’s a very interesting relationship.

[1] Something to try first – and even if this is not part of the
problem,
It may help you in debugging – is to name the relationships more
directly.
In PeContainer, name them “parentpage” and “childpages”, etc.

[2] I think your problem might lie in the fact that in your Page model
you
have only declared one relationship, when really there are two. Consider
the
case of a Book, which has an author and an editor, both of which are
People.
You would declare the relationships seperately, you would not say “has
many
People”. Similarly, in this case you should HABTM :parent_containers and
HABTM :child_containers.

Let us know if that gets you anywhere.

–
John Joseph B.
http://lyceum.ibiblio.org
http://blog.johnjosephbachir.org
aim/yim/msn/jabber.org/gtalk: johnjosephbachir
713-494-2704
http://jjb.cc

3

I have a problem with the relations of a model. The problem

Page
---->PeContainer
-------->Page
------------>PeContainer

So my mainproblem is to get the parentpage of the
PeContainer. I can only access the childpages. Can anyone
help? Thanks in advance!

Looks to me like your page model is incorrect, judging from your text
diagram. Assuming your model is a tree with alternating node types, you
probably want:

Page:
belongs_to :pe_container (parent)
has_many :pe_containers (children)

PeContainer:
belongs_to :page (parent)
has_many :pages (children)

  • donald
4

On 4/10/07, Ball, Donald A Jr (Library) [email protected]
wrote:

belongs_to :page (parent)
has_many :pages (children)

Yes, Donald’s suggestion is better than mine :slight_smile:

(although I would still name them more specifically)

–
John Joseph B.
http://lyceum.ibiblio.org
http://blog.johnjosephbachir.org
aim/yim/msn/jabber.org/gtalk: johnjosephbachir
713-494-2704
http://jjb.cc

5

Dear all!

Thanks for fast answering.

I changed the Modelrelations to the settings Donald wrote. But this
didn’t help.

I can’t rename my models, because I have an unlimited tree. So here is
an example of what i do:

I have a page (id=1)
This page has a container (id=1)
This Container has 2 pages (id=2 & id=3)
Page 1 has a container (id=2)
Page 2 has a container (id=3)

So now I have to walk up the tree. So if I have the container (id=1) I
need to get the parentpage (id=1), but I only can access the 2
childpages. So is this issue resolvable?

Thanks in advance!

Kind regards
Alex

On 10 Apr., 20:10, “John Joseph B.” [email protected]

6

On 4/10/07, physalias [email protected] wrote:

So my mainproblem is to get the parentpage of the PeContainer. I can
only access the childpages. Can anyone help? Thanks in advance!

I just re-read your email and realized that I did not address the
problem
you stated :). But I think making your relationships more explicit is a
good
place to start.

–
John Joseph B.
http://lyceum.ibiblio.org
http://blog.johnjosephbachir.org
aim/yim/msn/jabber.org/gtalk: johnjosephbachir
713-494-2704
http://jjb.cc