Why isn't my association object id being populated?

In my Rails app, I have two models, Estimate and Client, which both have a belongs_to relationship to State (as in U.S. states).

If I create a simple hash like this:

properties = {:state => State.first}

... I can build a Client in the Rails console like this:

c = Client.new(properties)

... and it shows up with a state_id of 1, as expected.

However, if I try the same with an Estimate, like this:

e = Estimate.new(properties)

... it never sets the state_id, so I can't save the association.

The tables for Estimate an开发者_运维知识库d Client have identical state_id columns (int 11). The association is the same. The State object is the same.

What could be causing this difference?

Update

This issue was attr_accessible as Misha pointed out. Another symptom we discovered was that Estimate.state = State.first returned NoMethodError: undefined method state=

Have you set attr_accessible in your Estimate model? If so, state may not be accessible and can only be set like this:

e = Estimate.new
e.state = State.first

Update

Note that state= is an instance method, not a class method.

This does not work:

Estimate.state = State.first

This does work:

e = Estimate.new
e.state = State.first