I have a bunch of 'kid' objects saved already and I want to create a parent object which is linked to the kids via a 'relative' model.
This object gives me a many-to-many, through relatives.
To be clear: the user visits the 'parents' page, clicks create parents and is presented with a form that lets them name the parent and add up to four children to this parent (by creating 'relatives'), each of these 'relations' is also named - that's an important part. So, I could name the relation 'step son' or 'son', for instance.
Here's the code I have so far:
class Kid < ActiveRecord::Base
has_many :relatives
has_many :parents, through: :relatives
end
class Parent < ActiveRecord::Base
has_many :relatives
has_many :kids, through: :relatives
accepts_nested_attributes_for :relatives,
:reject_if => lambda { |a| a[:content].blank? },
:allow_destroy => true
end
class Relative < ActiveRecord::Base
belongs_to :parent
belongs_to :kid
end
class ParentsController < ApplicationController
before_action :set_parent, only: [:show, :edit, :update, :destroy]
before_action :lookup_kids, only: [:new, :edit]
# GET /parents
# GET /parents.json
def index
@parents = Parent.all
end
# GET /parents/1
# GET /parents/1.json
def show
end
# GET /parents/new
def new
@parent = Parent.new
4.times { @parent.relatives.build }
end
# GET /parents/1/edit
def edit
end
# POST /parents
# POST /parents.json
def create
@parent = Parent.new(parent_params)
parent_params[:relatives_attributes].each do |k,r|
@parent.relatives.build(r.except(:_destroy))
end
respond_to do |format|
if @parent.save
format.html { redirect_to @parent, notice: 'Parent was successfully created.' }
format.json { render :show, status: :created, location: @parent }
else
format.html { render :new }
format.json { render json: @parent.errors, status: :unprocessable_entity }
end
end
end
# cut for brevity.
private
# Use callbacks to share common setup or constraints between actions.
def set_parent
@parent = Parent.find(params[:id])
end
def parent_params
params.require(:parent).permit(:name,
relatives_attributes: [:parent_id, :kid_id, :relationship, :_destroy])
end
def lookup_kids
@kids = Kid.all #for this nursery.
end
end
<%= form_for(@parent) do |f| %>
<% if @parent.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(@parent.errors.count, "error") %> prohibited this parent from being saved:</h2>
<ul>
<% @parent.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :name %><br>
<%= f.text_field :name %>
</div>
<h4>Kids:</h4>
<%= f.fields_for :relatives do |r| %>
<%= r.label :kid %>
<%= r.collection_select :kid_id,
@kids, :id, :name, include_blank: true%>
<%= r.label :relationship %>
<%= r.text_field :relationship %>
<%= r.check_box :_destroy %>
<%= r.label :_destroy, "Remove" %>
<br/>
<% end %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
ActiveRecord::Schema.define(version: 20151030113634) do
create_table "kids", force: :cascade do |t|
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "parents", force: :cascade do |t|
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "relatives", force: :cascade do |t|
t.string "relationship"
t.integer "parent_id"
t.integer "kid_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
add_index "relatives", ["kid_id"], name: "index_relatives_on_kid_id"
add_index "relatives", ["parent_id"], name: "index_relatives_on_parent_id"
end
When I get to 'create' in the parents controller, I can see the right parameters are getting through but the relationship records aren't being saved. SHouldn't this happen automatically?
I've tried looping through the :relatives_attributes but that doesn't seem to work with 'build'.
How am I suppsed to get the 'relatives' records to save?
EDIT: adding parameters posted:
parent"=>{
"name"=>"Dad",
"relatives_attributes"=>{
"0"=>{"kid_id"=>"2", "relationship"=>"Son", "_destroy"=>"0"},
"1"=>{"kid_id"=>"", "relationship"=>"", "_destroy"=>"0"},
"2"=>{"kid_id"=>"", "relationship"=>"", "_destroy"=>"0"},
"3"=>{"kid_id"=>"", "relationship"=>"", "_destroy"=>"0"}}}
Edit: I've updated this to show my latest edit - note the 'parent_params[:relatives_attributes].each do |k,r|' in the controller. This now saves the kid records but the only problem is, it also saves the fields that are blank! So I have 'relative' records with null values for kid records. How can I stop it saving empty fields (or creating empty relative records)?
The answer was to build each sub-record of relative, like so:
parent_params[:relatives_attributes].each do |k,r|
@parent.relatives.build(r.except(:_destroy))
end
Before calling @parent.save.
However, I'm still having issues getting rid of the blank records. So if anyone has an answer to that problem, please comment here - or if there's a better or more traditional way of doing this, hit me up. Follow up question here: Why is this reject_if in my model not rejecting blank records?
You are almost there, depending upon how your form submission is, you most likely need an accepts_nested_attribute_for in your Relative associative class as well:
class Relative
belongs_to :parent
accepts_nested_attributes_for :parent
belongs_to :kid
accepts_nested_attributes_for :kid
end
If this doesn't work, then please submit your params that are passed into the controller and we can adjust accordingly
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.