Active Record Validations — Ruby on Rails Guides

This guide teaches you how to validate Active Record objects before saving them to the database using Active Record's validations feature.After reading this guide, you will know: How to use the built-in Active Record validations and options. How to check the validity of objects. How to create conditional and strict validations. How to create your own custom validation methods. How to work with the validation error messages and displaying them in views.