Rails Model Reference
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rails new store- Create a new Rails app from scratch in a new store folder.
The following commands are entered in the terminal in your app's directory:
bundle install- Install the gems (bundled Ruby libraries) for your Rails App.
rails generate model Product name:string- Create Product model with a column
name(which will store strings of text).
rails g migration AddPriceToProducts price:integer- generates the migration file to add an integer price column to the product table.
rake db:migrate- Run migration files to apply changes to your database.
rake test- Run your application's tests.
You can connect with your app/database and perform standard CRUD operations in the Rails console. This is useful for trying code out.
rails c) - Enter this command in your terminal to start the Rails console.
reload!- Enter this in your running Rails console to reload changes
(See Active Record Migrations and the Rails Command Line for more.)
These are the 4 basic "CRUD" operations:
- Create -
Product .create(name: "Phonograph" , description: "Records sound" )- Creates and saves a new record to the database. Use
.newto instantiate an object without saving it until
- Read - There are many methods for reading data, such as:
products = Product .all- return collection of all products
products = Product .where(name: "Hammer" , price: 10)- returns all products with both these attributes
product = Product .find_by(name: "Cow" )- returns first product named "Cow"
- Update - After retrieving a record, you can modify and save it:
product.description = "It moos"
- Delete - Don't like your Cow? You can remove it from the database:
See Active Record Basics and Active Record Query Interface for more.
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