Join Kevin Skoglund for an in-depth discussion in this video Query methods: Conditions, part of Ruby on Rails 3 Essential Training.
We've seen how to perform some very simple finds, but they are really…rudimentary, and they don't really unlock the power of being able to find…exactly the information that we're looking for in the database at any certain time.…In order to construct those kinds of queries, we're going to need to use…Rails query methods.…The first one we're going to look at are the Conditions.…The conditions are going to let you specify what conditions the data ought to…meet before it gets returned to you.…So we can say I want all subjects where X is true, and Y is true, and Z is true.…That would be conditions.…
So let's look at how we do it in Rails.…We're going to be using the new ActiveRelation query methods.…The older way of doing it, the old query methods, are going to be deprecated in…Rails 3.1 and removed completely in Rails 3.2.…So we have a little bit of a grace period.…Right now, they work just fine.…In Rails 3.1, we're going to start getting complaints in our error logs saying,…"Hey, be careful about using this. It's about to go away."…
- Understanding MVC (Model View Controller ) architecture
- Routing browser requests through the framework
- Responding to requests with dynamic content
- Defining associations and database relationships
- Creating, reading, updating and deleting records
- Working with forms
- Validating form data
- Reviewing built-in security features
- Authenticating users and managing user access
- Debugging and error handling
Skill Level Beginner
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
12. Data Validation
13. User Authentication
14. Improving the Simple CMS
15. Debugging and Error Handling
16. Introducing More Advanced Topics
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