NumericalityConstraintChecker.md

Imagine your model has validates :age, numericality: { greater_than_or_equal_to: 0 } validation but does not have a CHECK constraint for the field in the database. In that case, invalid values can still be inserted outside your model validations. This checker helps ensure numericality validations are backed by a database CHECK constraint.

numericality validators without a range option (e.g. bare numericality: true) are skipped, since no CHECK constraint can express them.