A complex migration may involve processes that Active Record does not know how to reverse. You can use reversible to specify what to do when a migration is run and when it needs to be rolled back. For example: class ExampleMigration < ActiveRecord::Migration def change create_table :distributors do |t| t.string :zipcode […]
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Validations in Ruby
Active Record allows you to check the state of a model before it is written to the database. There are several methods that can be used to check your models and validate that an attribute’s value is non-empty, unique (not existing in the database), conforms to a certain format, and many more. Validation is a […]