Please refer to 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
and now refer update_attributes
and look at its 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
uses save(false)
whereas 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 validations associated with save
.
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])
Tip: update_attribute
is being deprecated in Rails 4 via Commit a7f4b0a1. It removes update_attribute
in favor of update_column
.
update_attribute
This method update single attribute of object without invoking model based validation.
obj = Model.find_by_id(params[:id])
obj.update_attribute :language, “java”
update_attributes
This method update multiple attribute of single object and also pass model based validation.
attributes = {:name => “BalaChandar”, :age => 23}
obj = Model.find_by_id(params[:id])
obj.update_attributes(attributes)
Hope this answer will clear out when to use what method of active record.
Also worth noting is that with update_attribute
, the desired attribute to be updated doesn't need to be white listed with attr_accessible
to update it as opposed to the mass assignment method update_attributes
which will only update attr_accessible
specified attributes.
update_attribute
simply updates only one attribute of a model, but we can pass multiple attributes in update_attributes
method.
Example:
user = User.last
#update_attribute
user.update_attribute(:status, "active")
It pass the validation
#update_attributes
user.update_attributes(first_name: 'update name', status: "active")
it doesn't update if validation fails.
You might be interested in visiting this blog post concerning all the possible ways to assign an attribute or update record (updated to Rails 4) update_attribute, update, update_column, update_columns etc.
http://www.davidverhasselt.com/set-attributes-in-activerecord/. For example it differs in aspects such as running validations, touching object's updated_at or triggering callbacks.
As an answer to the OP's question update_attribute
does not by pass callbacks.
Great answers. notice that as for ruby 1.9 and above you could (and i think should) use the new hash syntax for update_attributes:
Model.update_attributes(column1: "data", column2: "data")
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