1. At a computer system, a method for allowing a computer system user to extend the functionality of a data-centric software application, the method comprising the acts of: instantiating the data-centric software application, the data-centric application having one or more portions of business logic categorized and associated with one or more items of data-centric application functionality defined in a schema; receiving customization input to customize at least one of the one or more portions of business logic; formulating a representative model corresponding to at least one of the one or more portions of customized business logic; applying the representative model to the schema to generate a customized schema that extends the business logic of the data-centric software application; and instantiating the data-centric software application in accordance with the customized schema to customize the functionality of the business logic in the data-centric software application.