Validations in Ruby
From the Ruby on Rails cheat sheet · Models & Active Record · verified Jul 2026
Validations
Validate model data before saving
ruby
class User < ApplicationRecord
validates :email, presence: true, uniqueness: true
validates :name, presence: true, length: { minimum: 2 }
validates :age, numericality: { greater_than: 18 }
end✅ Validations run before save/create/update
💡 Use presence: true for required fields
🔍 Custom validations via validate method
⚡ Conditional validations with if/unless
modelsvalidationsdata-integrity