Hi i'm having a problem with a rails association. I have the Table Users and the table Roles. Here are my migrations:
class CreateUsers < ActiveRecord::Migration[5.2]
def change
create_table :users do |t|
t.string :email
t.string :password_digest
t.belongs_to :role, index: true, foreign_key: true
t.timestamps
end
end
end
class CreateRoles < ActiveRecord::Migration[5.2]
def change
create_table :roles do |t|
t.string :name
t.string :code
t.timestamps
end
end
end
Im having the problem when I create a user with a role that I had previously created
Role.create(name: 'Super Admin', code: 'super_admin')
User.create(email: 'a#b.com', password: 'abcdefg', role_id: 1)
When I try to do User.first.role I get that the method role is undefined. As far as i know When i do that i should get an active record with the role.
What i am doing wrong. Please Help
You need to add the relation to your model. In user.rb:
class User < ApplicationRecord
belongs_to :role
# other code
end
It will generate the ActiveRecord methods you are looking for.
Related
I have the following migrations:
class CreateMothers < ActiveRecord::Migration[5.0]
def change
create_table :mothers do |t|
t.string :name
t.timestamps
end
end
end
and:
class CreateSons < ActiveRecord::Migration[5.0]
def change
create_table :sons do |t|
t.string :name
t.references :mother
t.timestamps
end
end
end
Whenever I try to save a Son object with the mother_id field blank, I get the error: "Mother must exist"
Is there a way to save this without the mother_id field?
In your Son model, just add the optional param to make it work:
class Son < ApplicationRecord
belongs_to :mother, optional: true
end
In default, rails set it to be true, so let use false instead, the detail was described here
I have a rails application with
1)User Model
class User < ActiveRecord::Base
has_secure_password
has_many :projects
end
2) Project Model
class Project < ActiveRecord::Base
belongs_to :user
end
3) CreateUser in db/migrate
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :first_name
t.string :last_name
t.string :email
t.string :password_digest
t.references :projects
t.timestamps null: false
end
end
end
4) CreateProject in db/migrarte
class CreateProjects < ActiveRecord::Migration
def change
create_table :projects do |t|
t.string :name
t.string :description
t.references :users
t.timestamps null: false
end
end
end
Now in my Controller, I have a function
def create
#project = Project.new(project_params)
#user = User.find(session[:user_id])
if #project.save
#user.projects << Project.find(#project.id)
redirect_to '/'
else
redirect_to '/project/create'
end
end
But when i call http://localhost:3000/project/new, I receive following error :-
-NoMethodError in ProjectController#create
-undefined method `projects' for # User
with
#user.projects << Project.find(#project.id)
highlighted in the extracted source.
Am I entering the record into has_many relationship correct, or is my syntax wrong?
I ran the following code in the console the server,
user = User.find(1)
user.projects
I received this error message:
NoMethodError: undefined method `projects' for #<User:0x00000001f5b508>
from /home/harshil/.rvm/gems/ruby-2.2.1/gems/activemodel-4.2.4/lib/active_model/attribute_methods.rb:433:in `method_missing'
from /home/harshil/.rvm/gems/ruby-2.2.1/gems/activemodel-4.2.4/lib/active_model/attribute_methods.rb:433:in `method_missing'
Thanks
It seems the CreateUser migration is incorrect. It should not reference the projects. Projects should reference the User, which you have done correctly.
I believe this is confusing ActiveRecord
try removing t.references :projects from the UserCreate migration and try again
I have a problem with copying database records. I have a simple model User, that contains one-to-many relation with Language model and many-to-many relation with Skill model. I wanted to use amoeba gem to copy records with all associations. One-to-many copying works fine, but many-to-many doesn't copy at all.
Here's the code of User and Skill model:
user.rb
class User < ActiveRecord::Base
belongs_to :language
has_and_belongs_to_many :skills
validates_presence_of :email, :name
validates :email,
presence: { with: true, message: "cannot be empty" },
uniqueness: { with: true, message: "already exists in database" }
amoeba do
enable
end
end
skill.rb
class Skill < ActiveRecord::Base
has_and_belongs_to_many :users
end
I have also migration files that crates users, skills and skills_users tables:
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :name, null: false
t.string :email, null: false
t.references :language
t.timestamps null: false
end
end
end
.
class CreateSkills < ActiveRecord::Migration
def change
create_table :skills do |t|
t.string :name
t.timestamps null: false
end
end
end
.
class AddUsersSkillsTable < ActiveRecord::Migration
def change
create_table 'skills_users', :id => false do |t|
t.column :user_id, :integer
t.column :skill_id, :integer
end
end
end
Controller action 'show' in users_controller looks like this:
def copy
#user_copy = #user.dup
if #user_copy.save(validate: false)
redirect_to action: "index"
end
end
I tried copying relations in user.rb like this, but it didnt work:
amoeba do
enable
clone [:skills]
end
What may cause the problem?
Ok, I found the mistake. I wrote
#user_copy = #user.dup
in the controller file instead of
#user_copy = #user.amoeba_dup
I am trying to create a model in rails named chat, where I have two columns user1 and user2, and I want to store the user object in these. In grails, I do this simply as
class Chat {
User user1
User user2
Date chatStartedOn
}
and I am done. I did somewhat the same for rails
rails generate model Chat user1:User user2:User chatStartedOn:date
but I run db:migrate it showing me the error
undefined method `User' for #<ActiveRecord::ConnectionAdapters::TableDefinition
my user migrate file
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :username
t.string :email
t.string :encrypted_password
t.string :salt
t.timestamps
end
end
end
Please guide me on how I save user's object in chat table.
Try this
rails generate migration CreateChats
You can then add this code in your Chat migration file
class CreateChats < ActiveRecord::Migration
def change
create_table :chats do |t|
t.integer :user1_id, :references => [:users, :id]
t.integer :user2_id, :references => [:users, :id]
t.date :chatStartedOn
t.timestamps
end
end
end
you would then need to add the associations
Model user.rb
has_one :chat
Model chat.rb
belongs_to :user1, :class_name => "User"
belongs_to :user2, :class_name => "User"
Sorry, i'am newbie
I have database:
Migrate
-Mst_group tble
class CreateMstGroups < ActiveRecord::Migration
def self.up
create_table :mst_groups do |t|
t.string :group_name
end
end
end
-Mst_japan
class CreateMstJapans < ActiveRecord::Migration
def self.up
create_table :mst_japans do |t|
t.string :name_level
end
end
end
-Tbl_user
class CreateTblUsers < ActiveRecord::Migration
def self.up
create_table :tbl_users do |t|
t.string :login_name, :null =>false,:limit =>15
t.string :password,:null =>false,:limit =>50
t.string :full_name,:null =>false
t.string :full_name_kana
t.string :email,:null =>false
t.string :tel,:null =>false,:limit =>15
t.date :birthday,:null =>false
t.references :mst_groups
end
end
end
-Tbl_detail_user_japan
class CreateTblDetailUserJapans < ActiveRecord::Migration
def self.up
create_table :tbl_detail_user_japans do |t|
t.date :start_date
t.date :end_date
t.integer :total
t.references :tbl_users
t.references :mst_japans
end
end
end
Model
class MstGroup < ActiveRecord::Base
has_many :tbl_users
end
class MstJapan < ActiveRecord::Base
has_many :tbl_detail_user_japans
end
class TblUser < ActiveRecord::Base
belongs_to :mst_group
has_one :tbl_detail_user_japan
end
class TblDetailUserJapan < ActiveRecord::Base
belongs_to :tbl_user
belongs_to :mst_japan
end
Controller
def index
#user= ???????
end
How to write command select : login_name, full_name, full_name_kana, email, tel, group_name, name_lever, start_date, end_date, total in controller
It depends on how you want to retrieve the User object. You need to tell Rails how to find the TblUser object. If, for example, the user ID is known, let's say in a variable called 'id' then you would do:
def index
#user=TblUser.find(id)
end
It depends on your application logic how Rails would know which user you need. You may need an input from the user in case of log in, etc.
(Typically in Rails you would call the table 'Users', by convention tables and classes have the same name and then you wouldn't need to call the class TblUser)
That is all you need in the controller, you don't need to tell it which fields you want.
Then in the View you can access all the fields:
Fields on TblUser, example:
<%= #user.email %>
You can access the fields from related objects through the relations, example:
<%= #user.mst_group.group_name %>
Hope that helps to get you started.