similar to: How to create a child from a parent

I am working on an Rails application that uses a pretty complex category structure through out the site. I have defined a table to house all the info and a FK to reference parents within the table CREATE TABLE categories ( id int(11) NOT NULL auto_increment, name varchar(50) NOT NULL, parent_id int(11) default NULL, constraint fk_category_id foreign key (category_id) references

Hi all, I was wondering whether anyone could guide me to docu and code examples how to create and use a has_and_belongs_to_many relationship with a joining table where TWO columns are used to identify the relation to TWO alternative tables. Example: table 1: mothers [mother_id, name] table 2: fathers [father_id, name] table 3: children [child_id, name] joining table 4: children_parent

Basically, I''m trying to have a table called "categories" have a many to many relationship with itself. But I also want each catagory to be able to be "copied" into another category so it is essentially a child category to more than one parent. To me the obvious way of doing this is by creating another table called category_maps (and a model called CategoryMap).

I am trying to create a record with association. Within the create method, I would also like to pre-populate dependent (has_many) records from a template in the database. The child records are <u>mysteriously rolled back </u> if I insert them in a loop. If I try to insert a single child record, it works.I have read the books and tried to google my way out of this but am at a dead

hi. base from the cookbook example, where each categories can have many recipes, id like the categories to have multiple sub categories, unlimited levels. please show some code, as i am new to Ruby and Ruby On Rails. thanks -- Posted via http://www.ruby-forum.com/.

If i have a parent that has_many :children, and the child belongs_to :parent. Then when I add a new child to the parent like so: parent.children << Child.new, then shouldn''t the child also have a reference to the parent? but it doesn''t-- child.parent is nil-- what''s going on here? is this as it should be-- shouldn''t it have a reference to the

If I have... class Parent has_many :children end class Child belongs_to :parent end ...then... * Assigning a _new_ child during parent''s creation saves the child record with the parent''s id. child = Child.new Parent.create(:children => [child]) # Results in child being associated with parent * Assigning an existing child after a parent''s creation

How well does Rails deal with ActiveRecord classes mapping to self-referencing tables and other more interesting database complexities? i.e. Employees table with supervisor_id and mentor_id both self-referencing Employees on the primary key "id" or Categories table with relation table (Parent_Child_Categories) with foreign keys parent_id and child_id both referencing Categories.id

I am having a problem with ruby''s sort_by function. I want to sort a list of parent model objects based on the children of the parent models. Normally you might say sortedList = modelList.sort_by { |model| model[''someAttribute''] } What I am tring to do is sortedList = modelList.sort_by{ |model| model.children.find(:first, order=>"price desc" ).price}

To all: hi, i have implemented the associations in my models so i have a Parent model that has many Children model but i need to get a list of Parents that do not have children or Parents that have just 2 children or Parents that have children whose name is ''James'', or ''Sarah'', or ''Betty'' or Parents whose children do not have names like

Don't assume every disk <Item> has a <Parent> field. For floppy disks this is not the case. Thanks: Junqin Zhou --- v2v/input_ova.ml | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/v2v/input_ova.ml b/v2v/input_ova.ml index 95af2e5..9a9c10a 100644 --- a/v2v/input_ova.ml +++ b/v2v/input_ova.ml @@ -187,14 +187,17 @@ object for i = 0 to

disclaimer: am in the midst of my first ruby/rails project I have a situation where I want several child records to be created when a new parent record is created. The following represents my first stab at coding it, am I on the right track? Here is the model: parents ---------- id name children ---------- id parent_id name class Parent < ActiveRecord::Base has_many: children end

I have a simple object, Article, which has_one :parent of the same time. On my Show page for a given article there will be a "new child" button which will pass the current :id (or the current Article itself) to the new form. What is the proper way to hide a reference to this parent in the form so that when it is submitted back, the create method knows what to do with it?

Guys, I''m having a problem getting acts_as_tree working. It seems from the Agile book (p. 255) that acts_as_tree only supports one-to-one record relations, whereas I need many-to-many support. In other words, looking at the picture at the top of page 256 where where only 1 id is linked to 1 parent_id, I need multiple id''s linked to multiple parent_id''s - for

I''m trying to set up a directional self-referential HABTM to represent an arbitrary semi-hierarchical structure; it works for any data prepopulated into the db, but when I try to create a new relationship, I just get NULLs in both key columns (or 0''s if I turn on the no-null constraint). Here are the migrations: class CreateNodes < ActiveRecord::Migration def self.up

Hello. I hope this is the right place to describe my problem ? After upgrading to Rails version 1.1.2 from rails version 1.0.0, Web Service functional tests seem broken. I upgraded rails (as the root user / administrator) with: # gem update rails --include-dependencies then I upgraded my application (as myself) with: ? rake rails:update % rake rails:update:configs After these steps,

Hi, parent_id is the default name for the self-reference foreign key. What is the convention for naming the second parent id, the third? Thanks! gk -- Posted via http://www.ruby-forum.com/.

I have a couple of resources, one nested in the other, such that my resource spec in routes.rb is: map.resources :parents, :has_many => :children This will generate a route for a new child that assumes that the parent has already been saved, something like: /parents/:parent_id/children/new But what if I want a route that handles the case where the parent resource is also new, and thus

So I have a select list with a list of items. When a user selects an item, another select list should have its default selected item set to a specific item (the default associated with the first select list). This is in a form to create a new task. The first select list is a list of parent tasks. When one selects the parent task, the clients select list must default to the same client as its

I am trying to make a simple application which consists of contacts and their addresses. class Contact < ActiveRecord::Base has_many :addresses end class Address < ActiveRecord::Base belongs_to :contact end I would like to be able to edit/add addresses from within the edit/add of the contact. I scaffolded the contact and address objects and modified the contacts/_form partial as