Join Kevin Skoglund for an in-depth discussion in this video Solving migration problems, part of Ruby on Rails 3 Essential Training.
So far our migrations have been fairly straightforward and they have all run…smoothly but things can go wrong sometimes and I think it will be instructive…if I give you an example of how things can go wrong and then show you how to work through it.…So the first thing I need to do is I need to create a problem in my migration so…that we can deal with it.…I am inside my Rails app. I am going to start by doing rake db:migrate VERSION=0…and that will migrate down, there we go.…So I have now taken my database all the way down.…None of my migrations are in place right now.…
So let's open up the AlterUsers and let's change it so that password is going to…be just called broken.…So now when it tries to rename the column on admin_users, it's going to look…for column called broken, which doesn't exist and that's going to cause a problem for us.…Let's close it up and let's try it now.…So rake db:migrate.…It will run the first two successfully and then when it gets to the third one, it says oops!…Wait a minute.…
- 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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