Rails database system: `initialize': no such table: main.dinners (SQLite3::SQLException) error with one table column but not with the others columns

I have a simple rails 7 app where I can create a weekly menu. Then, users can select which day of the week they want.

I'm having a little trouble designing and make it in work. This is what I have so far:

rails generate model WeeklyMenu monday:references tuesday:references wednesday:references thursday:references friday:references saturday:references sunday:references
rails generate model Day lunch:references brunch:references dinner:references
rails generate model Meal title:string description:text

app/models/weekly_menu.rb

class WeeklyMenu < ApplicationRecord
  belongs_to :monday, class_name: 'Day'
  belongs_to :tuesday, class_name: 'Day'
  belongs_to :wednesday, class_name: 'Day'
  belongs_to :thursday, class_name: 'Day'
  belongs_to :friday, class_name: 'Day'
  belongs_to :saturday, class_name: 'Day'
  belongs_to :sunday, class_name: 'Day'
end

app/models/day.rb

class Day < ApplicationRecord
  belongs_to :lunch, class_name: 'Meal'
  belongs_to :brunch, class_name: 'Meal'
  belongs_to :dinner, class_name: 'Meal'
end

app/models/meal.rb

class Meal < ApplicationRecord
end

This is how I plan to create it but I'm getting and error with dinner, I don't know why, with lunch and brunch I don't have a problem:

v1 = Meal.create(title: 'Meal 1', description: 'Desc 1')
v2 = Meal.create(title: 'Meal 2', description: 'Desc 2')
v3 = Meal.create(title: 'Meal 3', description: 'Desc 3')


day2 = Day.create(lunch: v1) # fine
day3 = Day.create(lunch: v1, brunch: v2) # fine

day1 = Day.create(lunch: v1, brunch: v2, dinner: v3) # error
day4 = Day.create(cena: v3, brunch: v2, lunch: v1) # error


WeeklyMenu.create(
  monday: day1,
  tuesday: day2,
  wednesday: day1,
  thursday: day2,
  friday: day3
)

Error I'm getting:

  Day Create (0.7ms)  INSERT INTO "days" ("lunch_id", "brunch_id", "dinner_id", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?)  [["lunch_id", 6], ["brunch_id", 4], ["dinner_id", 5], ["created_at", "2023-07-03 02:21:40.793290"], ["updated_at", "2023-07-03 02:21:40.793290"]]
  TRANSACTION (0.1ms)  rollback transaction
/Users/dev/.rvm/gems/ruby-3.2.0/gems/sqlite3-1.6.3-arm64-darwin/lib/sqlite3/database.rb:152:in `initialize': SQLite3::SQLException: no such table: main.dinners (ActiveRecord::StatementInvalid)
/Users/dev/.rvm/gems/ruby-3.2.0/gems/sqlite3-1.6.3-arm64-darwin/lib/sqlite3/database.rb:152:in `initialize': no such table: main.dinners (SQLite3::SQLException)

> with lunch and brunch I don't have a problem

day2 = Day.create(lunch: v1) # fine
day3 = Day.create(lunch: v1, brunch: v2) # fine

That's not so fine because of Rails fail-open design. Take a look closer to day2 and day3: day2.valid2? => false.

Then the final error message in your example: SQLite3::SQLException: no such table: main.dinners. Rails tries to make a reference to dinners table that doesn't exist. It happens because of how the migration is defined:

    create_table :days do |t|
      t.references :lunch, null: false, foreign_key: true
      t.references :brunch, null: false, foreign_key: true
      t.references :dinner, null: false, foreign_key: true
    end

This schema won't work as expected. You can just use <meal>_id integers instead as follow:

create_table :days do |t|
  t.integer :lunch_id
  t.integer :brunch_id
  t.integer :dinner_id
end

With foreign keys:

create_table :days do |t|
  t.belongs_to :lunch, references: :meals, foreign_key: { to_table: 'meals' }
  t.belongs_to :brunch, references: :meals, foreign_key: { to_table: 'meals' }
  t.belongs_to :dinner, references: :meals, foreign_key: { to_table: 'meals' }
  t.timestamps
end