How I Use Rails Migrations for a New Project

Yesterday I started a new Rails project and it got me thinking about how I use migrations at the start of a project. I generally start with models and migrations when I begin a new project.

My usage of migrations tends to differ in the first day(s) of a Rails project. I will frequently roll the version of the data schema between 0 and the current version. I do this because if I forget a field/property on a model I don't define a new migration to add it, I just roll the schema back to 0 (rake db:migrate VERSION=0), change the create table migration, and then do a rake db:migrate to bring the schema right up to date. I find this the most pragmatic method early on and I continue to use it until I can't.

Why do I do this?

• Most of the fields in my model end up in one migration file.
• Having most of the fields in the create table migration helps my comprehension of the model. (I know I can look at schema.rb, or a SQL definition, but those don't have comments in them.)
• It keeps the number of migrations files small. Generally I only have one create table migration for each model when I get started.

Later as my project evolves I will use subsequent migrations to add/remove fields from tables, rename fields, etc.