Rails: update_attribute vs update_attributes

Question

Object.update_attribute(:only_one_field, "Some Value")
Object.update_attributes(:field1 => "value", :field2 => "value2", :field3 => "value3")

Both of these will update an object without having to explicitly tell AR to update.

Rails API says:

for update_attribute

Updates a single attribute and saves the record without going through the normal validation procedure. This is especially useful for boolean flags on existing records. The regular update_attribute method in Base is replaced with this when the validations module is mixed in, which it is by default.

for update_attributes

Updates all the attributes from the passed-in Hash and saves the record. If the object is invalid, the saving will fail and false will be returned.

So if I don't want to have the object validated I should use update_attribute. What if I have this update on a before_save, will it stackoverflow?

My question is does update_attribute also bypass the before save or just the validation.

Also, what is the correct syntax to pass a hash to update_attributes... check out my example at the top.

Answer 1

Hey please refer :- update_attribute

On clicking show source you will get following code

      # File vendor/rails/activerecord/lib/active_record/base.rb, line 2614
2614:       def update_attribute(name, value)
2615:         send(name.to_s + '=', value)
2616:         save(false)
2617:       end

& now refer update_attributes and look it's code you get

      # File vendor/rails/activerecord/lib/active_record/base.rb, line 2621
2621:       def update_attributes(attributes)
2622:         self.attributes = attributes
2623:         save
2624:    

end

the difference between two is update_attribute use save(false) where as update_attributes uses save or you can say save(true)

Sorry for the long description but what i want to say is important. save(perform_validation = true)) if perform_validation is false it bypasses (skips will be the proper word) all the before_* callbacks assosciated with save.

EDITED

For second question

Also, what is the correct syntax to pass a hash to update_attributes... check out my example at the top.

Your example is correct.

Object.update_attributes(:field1 => "value", :field2 => "value2", :field3 => "value3")

OR

Object.update_attributes :field1 => "value", :field2 => "value2", :field3 => "value3"

OR if you get all fields data & name in a hash say params[:user] here use just

Object.update_attributes(params[:user])

Answer 2

I think your question is if having an update_attribute in a before_save will lead to and endless loop (of update_attribute calls in before_save callbacks, originally triggered by an update_attribute call)

I'm pretty sure it does bypass the before_save callback since it doesn't actually save the record. You can also save a record without triggering validations by using

Model.save false