Question

I have two ActiveRecord models of the same class:

• #1: represents the current committed state of the row/model in the db
• #2: one that is potentially updated information for some of the fields of the first.

What I’m looking for is a way to update #1 on a field by field basis if #2 has a non-nil field. What’s the railsy way of doing this?

Answer 1

m1 = SomeModel.first()
m2 = SomeModel.first()

m2.some_attribute = "new value"

m2.attributes.each_pair {|k,v| m1.attributes[k] = v unless v.nil?}