So I'm writing my first Sinatra app, and using ActiveRecord as ORM.
so in my app.rb, I have a
class User < ActiveRecord::Base
validates_uniqueness_of :username
validates_presence_of :username
end
and create a migration and ran rake db:migrate on this
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :username
t.string :email
t.string :password
t.string :name
t.float :rating
t.timestamps
end
end
end
However, when in one of my methods I run
post "/create" do
u = User.new
u.save
redirect '/'
end
Sinatra crashes on the User.new and says
No GET data. on it. I've looked at tutorials and have no idea.
I figured it out.
I declared the User class before the function so it didn't see the class.
Related
I am trying to create an association between a User model and an Attendance model in which an attendee_id references a user. The association is a many to many relationship between users and concerts. The join table attendances has two fields
:attendee and :concert.
seed.rb file:
require 'faker'
Concert.destroy_all
User.destroy_all
Attendance.destroy_all
15.times do
Concert.create(band: Faker::RockBand.name, venue: "#{Faker::LordOfTheRings.location}", date: Faker::Date.forward(rand(30)), start_time: "8:00 PM")
end
5.times do |number|
User.create(first_name: Faker::Name.first_name, last_name: Faker::Name.last_name, email: "#{number}#email.com", password: "password")
end
concerts = Concert.all
users = User.all
15.times do
Attendance.create(attendee: users.sample, concert: concerts.sample)
end
Here are the models:
class Attendance < ApplicationRecord
belongs_to :attendee, class_name: "User"
belongs_to :concert
end
class Concert < ApplicationRecord
validates :band, :venue, :date, :start_time, presence: true
has_many :attendances
has_many :attendees, through: :attendances
end
class User < ApplicationRecord
validates :first_name, :last_name, :email, presence: true
validates_format_of :email, with: /#/
has_secure_password
has_many :attendances, foreign_key: :attendee_id
has_many :concerts, through: :attendances
end
Here are the migrations:
class CreateAttendances < ActiveRecord::Migration[5.0]
def change
create_table :attendances do |t|
t.references :attendee
t.references :concert, index: true
t.timestamps
end
end
end
class CreateUsers < ActiveRecord::Migration[5.0]
def change
create_table :users do |t|
t.string :first_name
t.string :last_name
t.string :email
t.string :password_digest
t.timestamps
end
end
end
class CreateConcerts < ActiveRecord::Migration[5.0]
def change
create_table :concerts do |t|
t.string :band
t.string :venue
t.datetime :date
t.time :start_time
t.timestamps
end
end
end
Looks like there are no attendee_id column
bundle exec rails db:reset (same as db:drop + db:create + db:migrate + db:seed)
And for tests bundle exec rails db:test:prepare
If it`s not solve the problem, i think, we need moar stacktraces)
I run bundle exec rake db:drop and then I created the database bundle exec rake db:create and bundle exec rake db:migrate I was then able to seed the database.
Please try to change t.references to special alias t.belongs_to.
It worked for me with Rails 5.2.1
i'm learning Rails and i'm doing an exercise to practice associations and migration files.
Currently, trying to make a models between users, auction item, and bids.
So far for the migrate files I have the following:
class CreateItem < ActiveRecord::Migration
def change
create_table :auction do |t|
t.string :item_name
t.string :condition
t.date :start_date
t.date :end_date
t.text :description
t.timestamps
end
end
end
class CreateBids < ActiveRecord::Migration
def change
create_table :bids do |t|
t.integer :user_id
t.integer :auction_id
t.timestamps
end
end
end
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :email
t.string :username
t.string :password_digest
t.timestamps
end
end
end
These are the following models:
class Bid < ActiveRecord::Base
belongs_to :bidder, class_name: "User", foreign_key: "bidder_id"
belongs_to :auction
end
class User < ActiveRecord::Base
has_many :bids
has_many :auctions, :foreign_key => 'bidder_id'
has_secure_password
end
class Auction < ActiveRecord::Base
belongs_to :seller, class_name: "User", foreign_key: :user_id
has_many :bids
has_many :bidders, through: :bids
end
Any suggestions or opinions? I'm currently trying to test the tables but auctions doesn't seem to be working...
Specifically, my auction table can't seem to find a user_id and therefore a user doesn't have any auctions.
foreign_key refers to the _id (by default) or any unique attribute used to associate the models.
I can't see bidder model, you need to replace them with user_id as they are associated to user model.
Refer for more details belongs_to
class CreateBids < ActiveRecord::Migration
def change
create_table :bids do |t|
t.integer :user_id **do not think this is correct**
t.integer :auction_id **or this one**
t.timestamps
end
end
end
You want to use something more along the lines of the following
class CreateGames < ActiveRecord::Migration[5.0]
def change
create_table :games do |t|
t.integer :total_time
t.references :version, foreign_key: true **#this is how a foreign key should be declared**
t.integer :total_points
t.timestamps
end
end
end
Alternatively, if you want to change things in future migrations you can always add a reference:
def change
add_reference :levels, :version, foreign_key: true
end
Let me explain :
I followed the M. Hartl tutorial and I did just like him with migrations. So now, I have the followings files in my db/migrate directory (I spare you the timestamps):
create_users.rb
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :name
t.string :email
t.timestamps
end
end
end
add_index_to_users_email.rb
class AddIndexToUsersEmail < ActiveRecord::Migration
def change
add_index :users, :email, unique: true
end
end
add_password_digest_to_users.rb
class AddPasswordDigestToUsers < ActiveRecord::Migration
def change
add_column :users, :password_digest, :string
end
end
add_remember_token_to_users.rb
class AddRememberTokenToUsers < ActiveRecord::Migration
def change
add_column :users, :remember_token, :string
add_index :users, :remember_token
end
end
add_admin_to_users.rb
class AddAdminToUsers < ActiveRecord::Migration
def change
add_column :users, :admin, :boolean, default: false
end
end
Is it possible to mix everything into create_users.rb like following, and delete the others migration files without any damage to my app ?
create_users.rb
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :name
t.string :email
t.string :password_digest
t.string :remember_token
t.boolean :admin, default: false
t.timestamps
end
add_index :users, :email, unique: true
add_index :users, :remember_token
end
end
Yes, it is possible. A straighforward strategy for that might be:
In order to avoid data loss, make a database dumb (create a DB backup)
Drop and recreate the database:
rake db:drop db:create
Have all migrations merged into a single file like you've shown
Run:
rake db:migrate
Restore the DB backup
Though, this may become tricky if you already have the application deployed on production.
I have update migrate script under db/migrate, and I did a
rake db:migrate
database script before update
class CreateStudents < ActiveRecord::Migration
def change
create_table :students do |t|
t.string :firstname
t.string :lastname
t.string :account
t.timestamps
end
end
end
databse script after update
class CreateStudents < ActiveRecord::Migration
def change
create_table :students do |t|
t.string :firstname
t.string :lastname
t.string :account
t.string :address
t.string :city
t.string :state
t.string :postcode
t.string :homephone
t.timestamps
end
end
end
after I dropped the old development.sqlite3 and old schema in schame.rb.
Say I added a few columns, but in the model these columns is missing.
But my model still is
class Student < ActiveRecord::Base
attr_accessible :firstname,:lastname,:account,
end
Is there a easy way I can bring the changes in new migrate script to model ?
If you want to allow for mass assignments of the other attributes, you can just add the keys to attr_accessible
class Student < ActiveRecord::Base
attr_accessible :firstname,:lastname,:account,:address, :city, :state, :postcode, :homephone
end
However, your model still has those attributes (or columns as you call them). You just can't do a mass assignment (like create or update_attributes) without making them attr_accessible first.
It looks like maybe you did rails generate migration which isn't meant to affect your model. I believe after you create your model everything afterward has to be done manually.
If you really want to effect changes to your database and model at the same time, your best bet might be to delete your migrations and model and do a rails generate scaffold (documentation) to create your entire scaffolding from scratch.
There are no problem to add the new columns manually in the model.
I am working on a small Android project with RoR server.
Here are the three models:
class User < ActiveRecord::Base
has_many :relations
has_many :friends, :through => :relations
attr_accessor :friend_ids
end
class Relation < ActiveRecord::Base
belongs_to :user
belongs_to :friend
end
class Friend < ActiveRecord::Base
has_many :relations
has_many :users, :through => :relations
end
class CreateUsers < ActiveRecord::Migration
def self.up
create_table :users do |t|
t.string :user_name
t.string :password
t.integer :city_id
t.integer :travelstyle_id
t.boolean :online
t.string :self_description
t.string :sex
t.integer :head_id
t.timestamps
end
end
def self.down
drop_table :users
end
end
class CreateFriends < ActiveRecord::Migration
def self.up
create_table :friends do |t|
t.string :user_name
t.integer :city_id
t.integer :travelstyle_id
t.string :self_description
t.string :sex
t.integer :head_id
t.timestamps
end
end
class CreateRelations < ActiveRecord::Migration
def self.up
create_table :relations do |t|
t.integer :user_id
t.integer :friend_id
t.timestamps
end
end
Model User uses model Relation to connect with model Friend. I use scaffold to creat the three models and add the relationship code in their model files. I also create a API controller to send xml file to Android application. Here is the controller code:
def find_friend
#user=User.where("id=?",params[:id])
#friend=#user.friends
respond_to do |format|
format.html
format.xml
end
end
Here is the problem, when I use the api(type in http://localhost:3000/api/find_friend/1.xml), the server throws a mistake:
NoMethodError in ApiController#find_friend
undefined method `friends' for #<ActiveRecord::Relation:0x3478a28>
app/controllers/api_controller.rb:21:in `find_friend'
I am new to Rails and have no idea where the wrong is. Do I have to add something in the "route.rb" or change the migration file?
In the rails console mode, I type in "user=User.find(1), friend=user.friends" and get the correct result.
~~~~(>_<)~~~~
The problem is the controller method "#user=User.where("id=?",params[:id])". The "where" method can not tell whether the result is an array or actually one object. If I use "#user=User.find(params[:id])", rails will be "smart enough" to know that "Oh, yes, this is just one object and it has a method called Friends because someone connects the two models together".
Learning Rails likes a marriage, you think you know well about her but sometimes you think "God actually I know nothing about the mysterious guy."