I'm trying to save data fetched from Sellix API into the db in my Rails application.
Basically, there are 4 models: products, coupons, orders, and feedback.
Sellix has its own unique id on every object called "uniqid" so I decided to use it as the primary key in my models as well.
For some models, I want to save references for other tables. For example, I want to have a coupon as a reference for orders to find out which coupon has been used when placing that order.
This is how two schemas are now:
create_table "coupons", id: false, force: :cascade do |t|
t.string "uniqid", null: false
t.string "code"
t.decimal "discount"
t.integer "used"
t.datetime "expire_at"
t.integer "created_at"
t.integer "updated_at"
t.integer "max_uses"
t.index ["uniqid"], name: "index_coupons_on_uniqid", unique: true
end
create_table "orders", id: false, force: :cascade do |t|
t.string "uniqid", null: false
t.string "order_type"
t.decimal "total"
t.decimal "crypto_exchange_rate"
t.string "customer_email"
t.string "gateway"
t.decimal "crypto_amount"
t.decimal "crypto_received"
t.string "country"
t.decimal "discount"
t.integer "created_at"
t.integer "updated_at"
t.string "coupon_uniqid"
t.index ["uniqid"], name: "index_orders_on_uniqid", unique: true
end
The coupon_uniqid on orders table is the reference to the relevant coupon.
The order object on Sellix API already has that reference so currently I can save it this way.
But when I display all orders, I have to use Coupon.find_by(uniqid: order.coupon_uniqid) and it always iterate through every coupon record in the local db to find it as below.
CACHE Coupon Load (0.0ms) SELECT "coupons".* FROM "coupons" WHERE "coupons"."uniqid" = $1 LIMIT $2 [["uniqid", "62e95dea17de385"], ["LIMIT", 1]]
I can get rid of that if I can keep the coupon reference instead of the uniqid.
That's basically what I want to figure out.
YAGNI. A better approach that you should consider is to just have your own primary key and treat the uniqid as a secondary identifier to be used when looking up records based on their external id.
That way everything just works with minimal configuration.
If you really want to break the conventions you can configure the type and name of the primary key when creating the table:
create_table :orders, id: :string, primary_key: :uniqid do |t|
# ...
end
class Order < ApplicationRecord
self.primary_key = :uniqid
end
Since this column won't automatically generate primary keys you'll need to deal with that in all your tests as well.
You then have to provide extra configuration when creating foreign key columns so that they are the same type and point to the right column on the other table:
class AddOrderIdToCoupons < ActiveRecord::Migration[7.0]
def change
add_reference :coupons, :order,
type: :string, # default is bigint
null: false,
foreign_key: { primary_key: "uniqid" }
end
end
And you also need to add configuration to all your assocations:
class Coupon < Application
belongs_to :order, primary_key: "uniqid"
end
class Order < Application
has_many :coupons, primary_key: "uniqid"
end
Related
cars.dealership_id can either refer to dealerships.id or dealerships.remote_id. How should I write my associations?
SCHEMA
create_table "cars", id: :serial, force: :cascade do |t|
t.string "name", limit: 255, null: false
t.integer "dealership_id", null: false
end
create_table "dealerships", id: :serial, force: :cascade do |t|
t.string "name", limit: 255, null: false
t.integer "remote_id", null: true
end
MODEL
class Car < ::ApplicationRecord
belongs_to :dealership,
class_name: '::Dealership',
foreign_key: :dealership_id,
primary_key: :remote_id
belongs_to :dealership,
class_name: '::Dealership',
foreign_key: :dealership_id,
primary_key: :id
end
cars.dealership_id can either refer to dealerships.id or dealerships.remote_id.
I'd suggest this design is problematic, and I'd recommend changing your database design as follows:
alter table cars
add constraint fk_cars_dealerships
foreign key (dealership_id)
references dealerships (id)
on update cascade
on delete restrict
;
With this change, the association becomes clear.
belongs_to :dealership
By default, create_table will create a primary key called id. You can change the name of the primary key with the :primary_key option (don’t forget to update the corresponding model) or, if you don’t want a primary key at all, you can pass the option id: false.
For creating primary key other than ID you can use the following.
class CreateContentUnits < ActiveRecord::Migration
def change
create_table :content_units, primary_key: :guoid do |t|
t.boolean :active, default: false
end
end
end
So now guoid will be used as primary key and now you can use your API ID as id in the model
Issue is I can't find why reference column id can't be inserted when create new record.
I have 3 table shop_plan, shop and app
Below is tables schema:
create_table "shop_plans", force: :cascade do |t|
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "shops", force: :cascade do |t|
t.string "url"
t.bigint "plan_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.index ["plan_id"], name: "index_shops_on_plan_id"
end
create_table "apps", force: :cascade do |t|
t.bigint "shop_id"
t.binint "amount"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.index ["app_id"], name: "index_apps_on_shop_id"
end
add_foreign_key "shops", "shop_plans", column: "plan_id"
add_foreign_key "apps", "shops"
And below is Model
class ShopPlan < ApplicationRecord
has_many :shop
end
class Shop < ApplicationRecord
belongs_to :shop_plan, class_name: 'ShopPlan', foreign_key: :plan_id
has_many :app
end
class App < ApplicationRecord
belongs_to :shop, class_name: 'Shop', foreign_key: :shop_id
end
There will be 1 default record added in seed.db for table shop_plan
ShopPlan.create(name: 'Basic')
ShopPlan and Shop are linked by plan_id column in Shop
Shop and App are linked by shop_id column in App
I pre-insert some value when user access index:
#basic_plan
#basicPlan = ShopPlan.where(name: "Basic").first
# if new shop registered, add to database
unless Shop.where(url: #shop_session.url).any?
shop = Shop.new
shop.url = #shop_session.url
shop.plan_id = #basicPlan.id
shop.save
end
This insert works well, however, when i run 2nd insert:
#shop= Shop.where(url: #shop_session.url).first
unless App.where(shop_id: #shop.id).any?
app = App.new
app.shop_id = #shop.id,
app.amount = 10
app.save
end
error occurs as somehow app.shop_id will not add in my #shop.id and it will return will error: {"shop":["must exist"]}
I even try hard-code app.shop_id =1 but it does not help and when I add in optional: true to app.db model, it will insert null
Appreciate if anyone can help point out why I get this error
EDIT: #arieljuod to be clear
1) I have to specific exact column class due to between Shop And Shop_Plan, i'm using a manual plan_id instead of using default shopplans_id columns.
2) I have update 1 column inside App and all that unless is just to do checking when debugging.
First of all, like #David pointed out, your associations names are not right. You have to set has_many :shops and has_many :apps so activerecord knows how to find the correct classes.
Second, you don't have to specify the class_name option if the class can be infered from the association name, so it can be belongs_to :shop and belongs_to :shop_plan, foreign_key: :plan_id. It works just fine with your setup, it's just a suggestion to remove unnecesary code.
Now, for your relationships, I think you shouldn't do those first any? new block manually, rails can handle those for you.
you could do something like
#basicPlan = ShopPlan.find_by(name: "Basic")
#this gives you the first record or creates a new one
#shop = #basicPlan.shops.where(url: #shop_session.url).first_or_create
#this will return the "app" of the shop if it already exists, and, if nil, it will create a new one
#app = #shop.app or #shop.create_app
I have found out the silly reason why my code does not work.
It's not because as_many :shops and has_many :app and also not because my code when creating the record.
It just due to silly comma ',' when creating new record in App at app.shop_id = #shop.id,, as I was keep switching between Ruby and JavaScript. Thank you #arieljuod and #David for your effort
I have two models connected with a has_and_belongs_to_many association: courses and semesters. rails_admin was only giving me the option to add semesters when creating a course, and not the other way around (and really, it's much more useful to add courses when creating a semester). I made some tweaks the migration:
def change
create_table "courses", force: :cascade do |t|
t.string "department"
t.integer "number"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "semesters", force: :cascade do |t|
t.integer "year"
t.string "season"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "semesters_courses", id: false, force: :cascade do |t|
t.integer "semester_id"
t.integer "course_id"
end
add_index "semesters_courses", ["course_id"], name: "index_semesters_courses_on_course_id"
add_index "semesters_courses", ["semester_id"], name: "index_semesters_courses_on_semester_id"
end
I renamed the intermediary table to semesters_courses from courses_semesters, just for clarity. Not only did this not solve the problem, but now when I try to add a new course, it 500s and tells me:
Could not find table 'courses_semesters'
I know I could make this go away by changing the name back, but I'm not sure where railsadmin is getting that name from (and suspect this to be the source of my problem). I've removed and reinstalled railsadmin, dropped and rewritten the tables, and cleared my browser's cache. When I search my entire project tree for "courses_semesters," I only get results in my error log.
New at Rails dev, so I assume I'm missing some config file somewhere that I need to update, but would love some help on where to find it.
You’re overwriting the join table name.
Option 1 you MUST specify the name of the join table in your models
app/models/course.rb
has_and_belongs_to_many :semesters, join_table: "semesters_courses"
app/models/semester.rb
has_and_belongs_to_many :courses, join_table: "semesters_courses"
Or Option 2 just rename your join table to "courses_semesters" by using migration.
rails g migration rename_courses_semesters
class RenameCoursesSemesters < ActiveRecord::Migration
def self.up
rename_table :semesters_courses, :courses_semesters
end
def self.down
rename_table :courses_semesters, :semesters_courses
end
end
Hope this answers your question.
I added a has_and_belongs_to_many between Product and Brand tables/models
This is how the models look like:
class Brand < ActiveRecord::Base
has_and_belongs_to_many :products
default_scope { order('name asc')}
end
class Product < ActiveRecord::Base
has_and_belongs_to_many :brands
end
These are the existing columns in the table:
[13] pry(main)> Brand
=> Brand(id: integer, name: string, created_at: datetime, updated_at: datetime, product_id: integer)
[11] pry(main)> Product
=> Product(id: integer, name: string, created_at: datetime, updated_at: datetime)
Join table db migration:
class CreateJoinTableProductsBrands < ActiveRecord::Migration
def change
create_join_table :products, :brands do |t|
t.integer :product_id
t.integer :brand_id
t.index [:product_id, :brand_id]
t.index [:brand_id, :product_id]
end
end
end
Questions:
As you will notice, the Brand table already had the product_id column. Should I change it to an array product_ids column? (I am using postgres)
Should I add brand_ids column to Product
Should I add ProductBrand model. I tried it but seems like Rails console didnt recognize it
class ProductBrand < ActiveRecord::Base
end
In ActiveAdmin what's the correct way of creating a new entry for Product or Brand such that a new record correctly links Product, Brand and ProductBrand entry?
I would highly recommend reading some tutorials and documentation that explain the fundamental difference between HATBM or HMT relationships in ActiveRecord. I think this would go a long way to answering your own questions.
Take the following tables below: Teams and Users (which could be equivalent to your brands and products). They likewise have a HATBM relationship both ways between them.
create_table "teams", force: :cascade do |t|
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "wins"
t.float "win_percentage"
end
create_table "teams_users", id: false, force: :cascade do |t|
t.integer "team_id", null: false
t.integer "user_id", null: false
end
add_index "teams_users", ["team_id", "user_id"], name: "index_teams_users_on_team_id_and_user_id", using: :btree
add_index "teams_users", ["user_id", "team_id"], name: "index_teams_users_on_user_id_and_team_id", using: :btree
create_table "users", force: :cascade do |t|
t.string "first_name"
t.string "last_name"
t.string "user_name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
Note that there is no foreign key (FK) of a user_id in the teams table, and no FK in the users table. The purpose of the join table is to join these 2 models hence no FK is needed in each to link them.
To answer your first 3 questions:
I would not change your product_ids column to an array. There is simply no need. This is the purpose of the join table.
I would not add a brand_ids column to product. Use your join table instead.
Unless you have a specific reason for requiring a ProductBrand model then you do not need it. If did require it then I would advocate the use of have_many through relationships. Follow the Rails conventions and if using ActiveRecord's HATBM association you don't need/want this.
This question/answer will help:
has_and_belongs_to_many vs has_many through
and an excellent post explaining join tables:
http://nishacodes.tumblr.com/post/73484141822/join-tables-heres-the-deal
schema.rb:
ActiveRecord::Schema.define(version: 20150324012404) do
create_table "groups", force: :cascade do |t|
t.string "title"
t.integer "teacher_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "groups_students", id: false, force: :cascade do |t|
t.integer "group_id"
t.integer "student_id"
end
add_index "groups_students", ["group_id"], name: "index_groups_students_on_group_id"
add_index "groups_students", ["student_id"], name: "index_groups_students_on_student_id"
create_table "users", force: :cascade do |t|
t.string "email", default: "", null: false
t.string "encrypted_password", default: "", null: false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", default: 0, null: false
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at"
t.datetime "updated_at"
t.boolean "admin", default: false
t.string "type"
t.integer "group_id"
end
add_index "users", ["email"], name: "index_users_on_email", unique: true
add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
end
group.rb:
class Group < ActiveRecord::Base
belongs_to :teacher
has_and_belongs_to_many :students
end
student.rb:
class Student < User
has_and_belongs_to_many :groups
end
I could have set a simple belongs_to and a has_many relationship between the student and group models, but I want students to be able to belong to more than one group, so I set up a HABTM association and corresponding join table.
I think I that right?
The question is, how do I, in the console, set a Student to belong to more than one group?
I have setup a User with 'type: Student' and I have two Groups. So...
In the console I do:
student = Student.first
Then, I want to set 'student' to belong to both Groups, but I don't know how to do this.
To set it to belong to one group I can do:
student.update_attributes(group_id: 1)
But how do make it belong to both groups? It would have two group_id's wouldn't it? I don't know how to set this.
If you need to see any of the other files, it's the 'handcode' branch here:
https://github.com/Yorkshireman/sebcoles/tree/handcode
The answers others have already provided are correct. But if you're working with id's you can also do something like this
student = Student.first
student.group_ids = 1,2,3,4
You don't need to set group_id for the User, the association is handled by the join table and the HABTM statement. You should remove group_id from the users table in the schema.
From memory you should be able to do something like this:
student = Student.first
groups = Group.all
student.groups << groups
student.save
See the active record guide on HABTM associations - specfically 4.4.1.3
Instead of habtm, just use the normal through and your life becomes easy. Make sure an id is generated for the association table (remove id:false)
create_table "group_students", force: :cascade do |t|
t.integer :group_id, nil:false
t.integer :student_id, nil:false
end
class Group < ActiveRecord::Base
has_many :group_students, dependent: :destroy, inverse_of :group
has_many :students, through :group_students
end
class Student < ActiveRecord::Base
has_many :group_students, dependent: :destroy, inverse_of :student
has_many :groups, through: :group_students
end
class GroupStudent < ActiveRecord::Base
belongs_to :group,
belongs_to :student
validates_presence_of :group, :student
end
Group.last.students << Student.last
or..
Student.last.groups << Group.last
Student.last.groups = [Group.find(1), Group.find(2)]
etc....
Ok, so it took me 3 days of all kinds of pain to work this out.
There was nothing wrong with my original code, except that I needed to remove the group_id from the user table.
roo's answer was correct, except that using 'group' as a variable name in the console confused Rails. This had led me to believe there was something wrong with my code, but there wasn't. You learn the hard way.
So, Students can be pushed into Groups like this:
To push a student into one group:
student = Student.first
OR
student = Student.find(1)
(or whatever number the id is)
group1 = Group.first
OR
group1 = Group.find(1)
student.groups << group1
To push into multiple groups (which was the original goal of this whole debacle:
student = Student.first
OR
student = Student.find(1)
allclasses = Group.all
student.groups << allclasses
To view your handywork:
student.groups
Works beautifully. The only problem I can see with my code is that it's possible to push the same student into a group twice, resulting in two duplicates of that student in one group. If anyone knows how to prevent this happening, I'm all ears.