Declarative validation

It's easy to set up declarative validation for an entity object to validate the data that is passed through the metadata file. Declarative validation is the validation added for an attribute or an entity object to fulfill a particular business validation. It is called declarative validation because we don't write any code to achieve the validation as all the business validations are achieved declaratively. The entity object holds the business rules that are defined to fulfill specific business needs such as a range check for an attribute value or to check if the attribute value provided by the user is a valid value from the list defined. The rules are incorporated to maintain a standard way to validate the data.

Knowing the lifecycle of an entity object

It is important to know the lifecycle of an entity object before knowing the validation that is applied to an entity object. The following diagram depicts the lifecycle of an entity:

When a new row is created using an...