[RUBY] Rails valid? And invalid?

A memorandum for learning Ruby on Rails. Reference article: Rails guide https://railsguides.jp/active_record_validations.html


Validation is done to save the correct data in the DB. Rails performs validation before saving the object to an ActiveRecord object. If an error occurs there, the object will not be saved. In short, do you meet the storage conditions for DB restrictions? It is a mechanism to check before saving at the DB level.

valid? And invalid?

valid? Can trigger validation manually. Returns true if there are no errors in the saved object Returns false on error.

class User < ApplicationRecord
	#Validation(Do not allow empty name)
	validates :name, presence: true

#This is true(Meet the conditions)
User.create(name: "Gonshiba").valid? 

#This is false(Does not meet the condition → name is empty)
User.create(name: "").valid?

invalid? Is a reverse check of valid ?, and only the returned Bool value is reversed. By the way, the create method does everything from object creation to saving.

Recommended Posts

Rails valid? And invalid?
Rails and FormData
[Rails] N + 1 problems and countermeasures
Rails: Difference between resources and resources
Rails Posts and User Linkage
[Rails] require method and permit method
Rails "render method" and "redirect method"
Rails Tutorial Records and Memorandum # 0
rails path and url methods
Rails is difficult and painful!
Introducing Bootstrap and Font-Awesome (Rails)
Rails is difficult and painful! Ⅱ
[Rails] strftime this and that
Rails web server and application server
[Rails] Save start time and end time
Enable jQuery and Bootstrap in Rails 6 (Rails 6)
[Rails] Difference between find and find_by
[Rails] Validation settings and Japanese localization
Rails model and table naming conventions
Remove "assets" and "turbolinks" in "Rails6".
CRUD features and MVC in Rails
[Rails] Differences and usage of each_with_index and each.with_index
Project ruby and rails version upgrade
Consideration about Rails and Clean Architecture
[rails] Difference between redirect_to and render
Install Webpacker and Yarn to run Rails
Building Rails 6 and PostgreSQL environment with Docker
Rails Addition of easy and easy login function
[Rails] [Memo] When to add = to <%%> and when not
[rails s error] md5.bundle and mysql installation error
Rails migration column changes and so on.
Rails validation and null: false Personal notes
[Rails] Difference between redirect_to and render [Beginner]