Terminal Command Mac Alter table SQLite3

What is the terminal command, or where is a go开发者_如何转开发od resource to get them, to alter a table. And, do I need to re run the $rake db:migrate after I do this? I am running RoR on Snow Leopard. Last question, can I make an already created column non-null.

UPDATE: figured out how to alter, just need to know if I need to rake db:migrate after alter.

good resource to get them, to alter a table

Check these to get a grasp at how migrations work

Rails Migrations Cheatsheet

Railsguides: Migrations

@run rake db:migrate: yes

@created to non-null: yes (Check 7.1 add_column and 7.2 change_column in the first link