CakePHP Validation

When to use

• The user needs rules that depend on the database, such as uniqueness or foreign-key existence, checked before a save commits.
• The user wants a custom validation rule, a named validation set, or a rule that applies only under certain conditions.
• The user needs to validate the shape of submitted data (required, length, format) before it is persisted in CakePHP.

When NOT to use

• Do not model "may this user perform this action" as a validation rule; that is an authorization concern handled by policies, not the Validator.
• Do not use this skill for Symfony Validator, Laravel validation, or Respect/Validation; the Validator and RulesChecker API is CakePHP specific.

Core guidance