How do I implement validations in Active Record?

How do I implement validations in Active Record?

You can implement validations in Active Record by using built-in validation methods like validates :attribute, presence: true.

Can you give me an example of a custom validation?

Sure! You can create a custom validation method in your model like this:

validate :custom_validation_method

def custom_validation_method
  errors.add(:attribute, 'must be valid') unless attribute_valid?
end

What are some common validation methods I should know?

Some common validation methods include validates_presence_of, validates_uniqueness_of, and validates_length_of.

How can I display validation errors in my form?

You can display validation errors in your form by iterating over @model.errors.full_messages and showing them in your view.