Ruby and Rails: Adding a column to a model without migrate

Question

There are a number of questions here about adding columns to a model via rails migration files and a rake db:migrate.

In this case, however, the application is basically a CRUD on top of an existing SQL Server database that is generated by another application. That is, I don't control it. Those who do control the database have added several columns to a table.

What I need is for the Rails app to respect the changes made to the database without assuming it has full control over the table structures.

I've tried plugging the new fields into the model and controller files, but sql queries give TinyTDS errors saying the new fields don't exist. Queries by hand (via SQL Server Management Studio) work fine. What am I missing? Why doesn't Rails recognize the new fields when they appear in the table model?

UPDATE:

It turns out that the problem is more subtle than I though when asking the initial question. As background, this application is set up with two databases, one production, one development/test. They are both on the same SQL Server database server. What's actually happening with the missing columns is that the Rails app pulls from production no matter what environment I use. Even when I change both environments to use the same development database (in database.yml), the app continues to query the production database.

Perhaps this is a problem between Rails and SQL Server. I've cleared all caches and cleared all database connections, but it makes no difference. It seems that the Rails app is caching the database name and login info somewhere.

One day I'd like to get this fixed, but for now I'll simply move the development database to another server for testing.

Answer 1

ActiveRecord has a cache of the table fields. If you want to reset the cache for a model without restarting your application, you can do:

MyModel.reset_column_information