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Database Validations Reference

Reference for CQL model validations.

Validation Macro

validate

Add validation rules to model fields.

validate field_name, rule: value, ...

Validation Rules

presence

Field must not be empty/nil.

validate name, presence: true

Fails when:

  • Value is nil
  • String is empty or whitespace only
  • Array/Hash is empty

length

String length constraints.

validate name, length: {min: 2}
validate name, length: {max: 100}
validate name, length: {min: 2, max: 100}
validate code, length: {is: 6}

Options:

  • min : Int32 - Minimum length
  • max : Int32 - Maximum length
  • is : Int32 - Exact length

format

Match regular expression.

validate email, format: {with: /\A[^@\s]+@[^@\s]+\z/}
validate slug, format: {with: /\A[a-z0-9-]+\z/}
validate phone, format: {with: /\A\d{10}\z/}

Options:

  • with : Regex - Pattern to match

numericality

Numeric value constraints.

validate age, numericality: {greater_than: 0}
validate age, numericality: {greater_than_or_equal_to: 18}
validate age, numericality: {less_than: 150}
validate age, numericality: {less_than_or_equal_to: 120}
validate quantity, numericality: {equal_to: 1}
validate count, numericality: {other_than: 0}
validate price, numericality: {odd: true}
validate pairs, numericality: {even: true}

Options:

  • greater_than : Number
  • greater_than_or_equal_to : Number
  • less_than : Number
  • less_than_or_equal_to : Number
  • equal_to : Number
  • other_than : Number
  • odd : Bool
  • even : Bool

inclusion

Value must be in set.

validate status, inclusion: {in: ["pending", "active", "archived"]}
validate role, inclusion: {in: Role.values.map(&.to_s)}

Options:

  • in : Array - Allowed values

exclusion

Value must not be in set.

validate username, exclusion: {in: ["admin", "root", "system"]}

Options:

  • in : Array - Forbidden values

uniqueness

Value must be unique in database.

validate email, uniqueness: true
validate slug, uniqueness: {scope: :category_id}
validate code, uniqueness: {case_sensitive: false}

Options:

  • scope : Symbol | Array(Symbol) - Columns to scope uniqueness
  • case_sensitive : Bool - Case-sensitive comparison (default: true)

acceptance

Boolean field must be true.

validate terms_accepted, acceptance: true

confirmation

Field must match confirmation field.

validate password, confirmation: true
# Expects password_confirmation field

Validation Options

allow_nil

Skip validation if value is nil.

validate age, numericality: {greater_than: 0}, allow_nil: true

allow_blank

Skip validation if value is blank.

validate bio, length: {max: 500}, allow_blank: true

on

Run validation only in specific context.

validate password, presence: true, on: :create
validate password, length: {min: 8}, on: :create

Values:

  • :create - Only on create
  • :update - Only on update
  • :save - On create and update (default)

if / unless

Conditional validation.

validate phone, presence: true, if: :requires_phone?
validate nickname, presence: true, unless: :has_name?

private def requires_phone?
  notification_method == "sms"
end

message

Custom error message.

validate email, presence: {message: "is required for registration"}
validate age, numericality: {greater_than: 0, message: "must be positive"}

Custom Validation

validate method

Override for custom logic.

class Order
  include CQL::Model(Order, Int64)

  property items : Array(OrderItem)
  property total : Float64

  def validate
    super  # Run standard validations

    if items.empty?
      errors.add(:items, "must have at least one item")
    end

    if total != items.sum(&.price)
      errors.add(:total, "doesn't match item sum")
    end
  end
end

errors.add

Add custom error.

errors.add(:field, "message")
errors.add(:base, "general error message")

Checking Validity

valid?

Returns true if all validations pass.

user = User.new(name: "")
user.valid?  # => false

invalid?

Returns true if any validation fails.

user.invalid?  # => true

errors

Access validation errors.

user.errors.each do |error|
  puts "#{error.field}: #{error.message}"
end

user.errors.full_messages  # => ["Name can't be blank"]
user.errors.on(:name)      # => ["can't be blank"]

Validation Lifecycle

  1. before_validation callback
  2. Run validations
  3. after_validation callback
  4. If valid, proceed with save
  5. If invalid, abort operation
class User
  include CQL::Model(User, Int64)

  before_validation :normalize_data

  private def normalize_data
    @email = email.downcase.strip
    @name = name.strip
  end
end

Complete Example

class User
  include CQL::Model(User, Int64)
  db_context MyDB, :users

  property id : Int64?
  property name : String
  property email : String
  property password_hash : String?
  property age : Int32?
  property role : String
  property terms_accepted : Bool

  # Basic validations
  validate name, presence: true, length: {min: 2, max: 100}
  validate email, presence: true, format: {with: /@/}, uniqueness: true
  validate role, inclusion: {in: ["user", "admin", "moderator"]}
  validate terms_accepted, acceptance: true, on: :create

  # Conditional validation
  validate age, numericality: {greater_than: 0, less_than: 150}, allow_nil: true

  # Password validation only on create
  validate password_hash, presence: true, on: :create

  # Custom validation
  def validate
    super

    if role == "admin" && !email.ends_with?("@company.com")
      errors.add(:email, "admins must use company email")
    end
  end
end

See Also