Why is rails setting ":null => false" on all my columns in schema.rb?

Question

Even if I never specify :null => false in my migrations that initially add columns to tables, rails still generates code in schema.rb that specifies the columns as having :null => false. Why is this? If I develop on my box, and then use rake db:schema:load on my production box, I'm going to get very different behavior!

Edit: Even if I delete schema.rb and run rake db:schema:dump, it still puts :null => false on the new schema even if it isn't defined like that in the actual database. It seems it can't tell whether or not a column is marked as allowing nulls. I'm using SQLite if that helps.

Answer 1

Reverting to ruby 1.8.7 did the trick for me.

No idea why though.

Answer 2

I really hate that this was so subtle, but the problem was I was using the sqlite3 gem instead of sqlite3-ruby. As soon as I corrected it in environment.rb, everything was better.