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Validation Methods

Ruby on Rails Validation methods

  • validates_presence_of

Attribute mustn’t be blank(nil,false,[],{})

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validates_presence_of :field_name
  • validates_length_of

Attribute must meet length requirements :is, :minimum, :maximum, :within, :in, :too_short, :too_long

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validates_length_of :field_name, :minimum => 100
  • validates_numericality_of

Attribute must be integer or floating number :less_than, :greater_than, :equal_to, :odd, :even, :greater_than_or_equal_to

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validates_numericality_of :field_name, :greater_than_or_equal_to => 5
  • validates_inclusion_of

Attribute must be in a list of choises. (array or range) :in

  • validates_exclusion_of

Attribute mustn’t be in a list of choises. (array or range) :in

  • validates_format_of

Attribute must match a regular expression. :with

  • validates_uniqueness_of

Attribute mustn’t exist in the database :case_sensitive, :scope

  • validates_acceptance_of

Attribute must be accepted :accept(expected value, 1)

  • validates_confirmation_of

Attribute must be confirmed by entering it twice creates a virtual blank attribute for confirmation.

  • validates_associated

Associated object or objects must all be valid.

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:allow_nil => true
#Skip valid if attribute is nil
:allow_blank => true
#Skip valid if attribute is blank

Example of Validations

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validates_presence_of :user_name
validates_length_of :user_name, :maximum => 50
validates_uniqueness_of :user_name

When we use like above, We diverge to DRY, instead of above

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validates :user_name, :presence => true
                     :length => {:maximum => 50}
                     :uniqueness => true

That’s all.

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