Category: Ruby on Rails

The Ruby on Rails framework follows the MVC pattern that implements REST architecture. One of the important constraints of REST is statelessness. It implies that each request sent by the client must have enough information for the server to handle and satisfy it, and that the server doesn’t hold on to the request data once it…

The Rails controller is the logical centre of your application. It coordinates the interaction between the user, the views, and the model. The controller is also a home to a number of important ancillary services. The following diagram explains how the controller interacts with the model and the view layer − The process for creating…

In the earlier chapters of this tutorial, we explained the Active Record ORM in Ruby on Rails framework. Active Record is an ORM (Object Relational Mapper) that connects objects whose data requires persistent storage to a relational database. One of the functionality of Active Record is to form Active Model. In this chapter, we will explore the features of Rails Active…

Rails Migration allows you to use Ruby to define changes to your database schema, making it possible to use a version control system to keep things synchronized with the actual code. Instead of writing schema modifications in pure SQL, you can use a Ruby Domain Specific Language (DSL) to make required changes to your table…

Read this chapter to learn the different ways to retrieve data from the database using Active Record. You generally need to execute the SELECT query in raw SQL to retrieve data from the tables in a database of any type (such as MySQL, PostgreSQL, Oracle SQLite etc.). In most cases, the Rails ORM implemented by…

Relational databases have tables related to each other, and their relationship is established with primary and foreign keys. In Rails, the Active Record associations allow you to define relationships between models. Associations indicate how your models relate to each other. When you set up an association between models, Rails migration defines the Primary Key and…

It is important that the state of an object of Active Record class is validated before saving the same in the underlying database. This is essential to ensure the integrity of the data. For example, your model might have email as one of the attributes. It must be ensured that the user enters a valid…

Rails Active Record is the Object/Relational Mapping (ORM) layer supplied with Rails. It closely follows the standard ORM model, which is as follows − Rails Active Records provide an interface and binding between the tables in a relational database and the Ruby program code that manipulates database records. Ruby method names are automatically generated from…

Before starting with this chapter, make sure your database server is up and running. Ruby on Rails recommends to create three databases – a database each for development, testing, and production environment. According to convention, their names should be − You should initialize all three of them and create a user and password for them…

In this chapter, we will create a simple but operational online library system for holding and managing the books. This application has a basic architecture and will be built using two ActiveRecord models to describe the types of data that is stored − Workflow for Creating Rails Applications A recommended work flow for creating Rails…