[RUBY] Frequently used methods in Active Record

Methods used in ActiveRecord

Method	role	Return value	Description example
valid?	Check if the target object is valid	true or false	user.valid?
save	Have the database save the target object	true or false	user.save
create	Generate and save the model at the same time	Success: the object itself Failure: Error	User.create(name: 'hoge', email: 'fuga')
destroy	Delete the target object	Success: the object itself Failure: Error	user.destroy
find	Get record from database with id in argument	Success: Target object Failure: Error	User.find(1)
find_by	Get the record from the database with key and value as arguments	Success: the object itself Failure: nil	User.find_by(name: 'hoge')
update	Pass the hash of the attribute to update the value in the database	Success: true or failure: error	user.update(name: 'hoge', email: 'fuga')
update_attribute	Update only specific attributes Key for the first argument, value for the second argument Can be updated by ignoring the verification conditions	Success: true or failure: error	user.update_attribute(:name, 'piyo')

Usage pattern

The return value of the save method will be true or false, so it will be used when implementing the controller's create action.

`hoge_controller.rb`


def create    
  tweet = Tweet.create(tweet_params)
  if tweet.save
    #Processing when saving is successful
  else
    #Processing when saving fails
  end
end