rails validators

# Step 1: Define a Rails model with attributes
class User < ApplicationRecord
  validates :username, presence: true, uniqueness: true, length: { minimum: 3, maximum: 30 }
  validates :email, presence: true, uniqueness: true, format: { with: URI::MailTo::EMAIL_REGEXP }
  validates :age, numericality: { greater_than_or_equal_to: 18, less_than_or_equal_to: 99 }
end

# Step 2: Presence Validator
validates :username, presence: true
validates :email, presence: true

# Step 3: Uniqueness Validator
validates :username, uniqueness: true
validates :email, uniqueness: true

# Step 4: Length Validator
validates :username, length: { minimum: 3, maximum: 30 }

# Step 5: Format Validator
validates :email, format: { with: URI::MailTo::EMAIL_REGEXP }

# Step 6: Numericality Validator
validates :age, numericality: { greater_than_or_equal_to: 18, less_than_or_equal_to: 99 }