Validation on update

Searched for it, but found nothing, so i open a new topic :confused:
I think it is very basic stuff…

My model has a validation rule like this:
validates_presence_of :title

If i try to save the model ( with an empty title-formfield
i get an error. hooray! that’s what i want!
okay i insert a valid title and everything is fine.

now i want to update the model (@mymodel.update) and - SURPRISE! - now
i can update title to an empty string “”! Why?

Even if i have this in my rule
validates_presence_of :title, :on => :update
i can update my model without an error and have an empty string for the
title in my database.

i dont get it. the API says:
update(id, attributes)
Finds the record from the passed id, instantly saves it with the passed
attributes (if the validation permits it), and returns it.

but it does not validate!!
i’m using rails 1.1.2

It looks like you’re confusing Model.update with
@model.update_attributes. Model.update(id, attributes) should be
called on the class, not an instance.

Person.update(1, { :name => ‘Jonathan’ })

Is equivalent to:

p = Person.find(1)
p.update_attributes({:name => ‘Jonathan’})

Surprisingly, p.update actually saves the record without looking at
the validation… that could be classed as misleading at best. You
should use update_attributes, not update.

ActiveRecord::Base#update is private in base.rb, but locking.rb does
not preserve its private status. Looks like a small bug, I’ll file it


Oh damn, that is indeed misleading. I didnt realize that update' is a private method. well, i usedupdate’ everywhere in my application to update stuff. :frowning:

Thanks for your help! I’m off to rewrite some code … :confused:

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