Join Kevin Skoglund for an in-depth discussion in this video Finding records, part of Ruby on Rails 4 Essential Training.
…As you're developing, you'll find that you're querying for existing…records far more often than you're creating, updating, or deleting them.…ActiveRecord offers many tools to make finding records easier.…Over the course of the next few movies,…we will learn how to construct queries in Rails.…We'll start with the simplest one first.…The one that we've already seen is one I call the primary key finder.…So if we have subject and then we call find(2) on it.…Two is the argument that we're passing in to the…find method, and the result is that it will go to…our database, it'll look for the subjects, and it'll try and…find a subject who's primary key matches what we've passed in.…
In our case, the primary key is going to be id,…so we'll look for something whose id is equal to two.…It will return either an object, an instance of the…subject that's been instantiated, or it will return an error.…And we saw that error in the last movie after we…destroyed the subject, we did a primary key find one more time.…And we got back an error, was an active record, record not found error.…
- Why use Ruby on Rails?
- Installing Ruby on Rails on Mac and Windows
- Rendering templates and redirecting requests
- Generating and running database migrations
- Creating, updating, and deleting records
- Understanding association types
- Using layouts, partials, and view helpers
- Incorporating assets using asset pipeline
- Validating form data
- Authenticating users and managing user access
- Architecting RESTful applications
- Debugging and error handing
Skill Level Intermediate
1. What Is Ruby on Rails?
2. Installing Ruby on Rails on a Mac
3. Installing Ruby on Rails on a Windows Machine
4. Getting Started
5. Controllers, Views, and Dynamic Content
6. Databases and Migrations
7. Models, ActiveRecord, and ActiveRelation
9. Controllers and CRUD
10. Layouts, Partials, and View Helpers
13. Data Validation
14. User Authentication
15. Improving the Simple CMS
16. REST and RESTful Routes
17. Debugging and Error Handling
18. Introducing More Advanced Topics
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