Validation

Question 1

How to add validation on presence?

Answer 1

validates :name, presence: true

Question 2

How to validate that value is blank?

Answer 2

validates :name, absence: true

Question 3

How to check that record is valid? or invalid?

Answer 3

• User.new(name: ‘a’).valid?

- User.new(name: ‘a’).invalid?

Question 4

How to show a list of errors?

Answer 4

u = User.new(name: ‘a’)

u. valid?
u. errors

Question 5

How to validate acceptance of the field? ( accept the agreement or not)

Answer 5

validates :terms_of_service, acceptance: true

User.new(terms_of_service: 0).valid? # false

Question 6

How to validate record formate with regexp?

Answer 6

validates :name, format: { with: /[a-z]/ }

Question 7

How to check that value is included in the given array?

Answer 7

validates :name, inclusion: { in: [‘a’, ‘b’] }

Question 8

How to validate length of the record?

Answer 8

validates :name, length: { minimum: 10, maximum: 20 }

Question 9

How to validate that value is a number?

Answer 9

validates :name, numericality: true

Question 10

What is the difference between validates and validate?

Answer 10

• “validate” for custom validation

- “validates” for rails validation

Question 11

How to add a custom validation?

Answer 11

validate :custom_validation

  def custom_validation
    errors.add(:name, 'custom_error') if true
  end

Question 12

How to validate that value is unique?

Answer 12

validates :name, uniqueness: true