So after alot of reading i found out that i dont need to plan my database ahead. I just start working on the application and do migrations on every change.
So for example if I decide to add something I add it via migration. Then on another migration I delete it for some reason. And in the end I decide to get it back. After a short time there will be a mess of migrations.
How do I keep track of them? Wouldnt be easier to think of the database structure in the first place?
You can see your database structure inside db/schema.rb which will show you all the tables, columns and indexes currently in your app.
Not as helpful if you're constantly changing a column, but you can also run rake db:migrate:status which will output a list of all migrations, and tell you whether they've been run or not.
Rails way is to do everything via migrations. As per your scenario it would be like:
migration1 #add column A
migration2 #remove column A
migration3 #add column A again
It seems like there are lots of migrations, but in practical scenario it will keep your database changes clean. Because at any given time when you do:
rake db:migrate
Rails will run only the pending migrations.
And at any given time you will see the db/schema.rb file with all the migrates and latest migration number as the version.
Having said that, if you want to revert a migration there are commands like rollback commands. Read more about migrations here.
