Validates

rubyonrails-talk
1

If I have a table: users(id, name, address, city)

How can I validate: Name must be entered, but address and city can be null, but if there is address, there also must be a city. So city can't be null, if address is not, but bouth address and city can be null.

validates_presence_of name validates ???

2

class User   validates_presence_of :name   validates_presence_of :city, :if => :address   validates_presence_of :address, :if => :city end