RAILS: Insert data into Join Model comes with unexpected behaviour - sql

Question

I don't quite understand why after inserting data in my join model, they came out with strange results.
Here are my models
StaffRateItem
class StaffRateItem < ActiveRecord::Base
has_many :staff_default_rate_settings
has_many :assignment_type_categories, through: :staff_default_rate_settings do
def create_staff_default_rate_setting(assignment_type_category, rates_amount_attr)
StaffDefaultRateSetting.create(rates_amount: rates_amount_attr){ self << assignment_type_category}
end
end
accepts_nested_attributes_for :staff_default_rate_settings
end
AssignmentTypeCategory
class AssignmentTypeCategory < ActiveRecord::Base
has_many :staff_default_rate_settings
has_many :staff_rate_items, through: :staff_default_rate_settings
end
StaffDefaultRateSetting
class StaffDefaultRateSetting < ActiveRecord::Base
belongs_to :staff_rate_item
belongs_to :assignment_type_category
end
Then under my StaffDefaultRateSetting Controller create method
def create
#staff_rate_item = StaffRateItem.new(staff_rate_item_params)
#assignment_type_category1 = AssignmentTypeCategory.find(params[:staff_rate_item][:staff_default_rate_setting][0][:assignment_type_category_id])
#assignment_type_category2 = AssignmentTypeCategory.find(params[:staff_rate_item][:staff_default_rate_setting][1][:assignment_type_category_id])
#assignment_type_category3 = AssignmentTypeCategory.find(params[:staff_rate_item][:staff_default_rate_setting][2][:assignment_type_category_id])
#staff_rate_item.assignment_type_categories.create_staff_default_rate_setting #assignment_type_category1, params[:staff_rate_item][:staff_default_rate_setting][0][:rates_amount]
#staff_rate_item.assignment_type_categories.create_staff_default_rate_setting #assignment_type_category2, params[:staff_rate_item][:staff_default_rate_setting][1][:rates_amount]
#staff_rate_item.assignment_type_categories.create_staff_default_rate_setting #assignment_type_category3, params[:staff_rate_item][:staff_default_rate_setting][2][:rates_amount]
respond_to do |format|
if #staff_rate_item.save
format.html { redirect_to staff_default_rate_settings_url, notice: 'Staff default rate setting was successfully created.' }
format.json { render action: 'show', status: :created, location: #staff_default_rate_setting }
else
format.html { render action: 'new' }
format.json { render json: #staff_default_rate_setting.errors, status: :unprocessable_entity }
end
end
end
Basically StaffDefaultRateSetting is the join model for the StaffRateItem and AssignmentTypeCategory models.
Thus under its physical table, it has its following fields.
id
staff_rate_item_id
assignment_type_category_id
rates_amount
created_at
updated_at
So what I'm saying that each time I insert a new staff_rate_item record, I expect to include three other specific assignment_type_category fields for that staff_rate_item record, along with their respective rate amounts. Thus the end result in the StaffDefaultRateSetting table is that I will see three records in there.
But instead I get the following result.
id | staff_rate_item_id | rates_amount | created_at | updated_at | assignment_type_category_id |
18 | | 20.00 | 2014-04-08 22:57:25.81432 | 2014-04-08 22:57:25.81432 | |
19 | | 20.00 | 2014-04-08 22:57:25.888068 | 2014-04-08 22:57:25.888068 | |
20 | | 20.00 | 2014-04-08 22:57:25.915939 | 2014-04-08 22:57:25.915939 | |
21 | 6 | | 2014-04-08 22:57:26.016725 | 2014-04-08 22:57:26.016725 | 1 |
22 | 6 | | 2014-04-08 22:57:26.021352 | 2014-04-08 22:57:26.021352 | 2 |
23 | 6 | | 2014-04-08 22:57:26.024253 | 2014-04-08 22:57:26.024253 | 3 |
If you look the rows carefully, I got 6 records instead of supposedly 3 records only. The rates amount were inserted into three separate rows whilst the rows with staff_rate_item_id and assignment_type_category_id are inserted independently - without the rate amounts!
This is clearly very wrong behaviour.
I've been search a lot for online to determine if there's something wrong with my model creation logic on StaffDefaultRateSetting layer.
def create_staff_default_rate_setting(assignment_type_category, rates_amount_attr)
StaffDefaultRateSetting.create(rates_amount: rates_amount_attr){ self << assignment_type_category}
end
Or maybe there's the basic setup of inserting join model data I failed grasp (and oughta know). Surely it must be something basic code to insert such simple join model creation. What did I do wrong here? I'm using PostgreSQL for development, not MySQL just fyi.
Any ideas would be greatly appreciated!

Answer 1

After spending sometime thinking about the problem, I went back to the drawing board and redo the basics again.
This time. I redo the code in the StaffDefaultRateSetting Controller
def create
#staff_rate_item = StaffRateItem.new(staff_rate_item_params)
#assignment_type_category1 = AssignmentTypeCategory.find(params[:staff_rate_item][:staff_default_rate_setting][0][:assignment_type_category_id])
#assignment_type_category2 = AssignmentTypeCategory.find(params[:staff_rate_item][:staff_default_rate_setting][1][:assignment_type_category_id])
#assignment_type_category3 = AssignmentTypeCategory.find(params[:staff_rate_item][:staff_default_rate_setting][2][:assignment_type_category_id])
#staff_rate_item.staff_default_rate_settings.create(assignment_type_category_id: #assignment_type_category1.id, rates_amount: params[:staff_rate_item][:staff_default_rate_setting][0][:rates_amount] )
#staff_rate_item.staff_default_rate_settings.create(assignment_type_category_id: #assignment_type_category2.id, rates_amount: params[:staff_rate_item][:staff_default_rate_setting][1][:rates_amount] )
#staff_rate_item.staff_default_rate_settings.create(assignment_type_category_id: #assignment_type_category3.id, rates_amount: params[:staff_rate_item][:staff_default_rate_setting][2][:rates_amount] )
respond_to do |format|
if #staff_rate_item.save
format.html { redirect_to staff_default_rate_settings_url, notice: 'Staff default rate setting was successfully created.' }
format.json { render action: 'show', status: :created, location: #staff_default_rate_setting }
else
format.html { render action: 'new' }
format.json { render json: #staff_default_rate_setting.errors, status: :unprocessable_entity }
end
end
end
I took out my def create method in StaffRateItem Model and I felt the rewritten code should be suffice to do the same task without worrying about the major hassles of trying fancy code to make the save data to work as I'm pressed for times to get my client's project underway. Cheers!