Define Data Validation

Group+ Edition

Data validation is a method to conditionally prevent records from being saved; it is separate from field level security and page layouts.

List common use cases for Data Validation

See “Useful validation formulas”.  A common usage would be to prevent an opportunity from being saved if the close date is in the past.

Describe when Data Validation Rules are enforced

Data validations are enforced whenever a record is saved.  This includes the data loader, mass transfer records, importing records, etc.  Validation rules during lead conversion are only active if enabled.  See “Validation Rule Considerations” for details.

Create Data Validation Rules

Validation rules are created per object, and make use of formulas.  I would strongly recommend reading and trying a few from the list “Useful Validation Formulas”.