1. A computer-implemented method for configuring a customized extension for an electronic database object, the method comprising: receiving one or more first user inputs for creating a set type, wherein the set type is an electronic database object that represents an attribute of one or more types of products that are for sale, and wherein the first user inputs specify one or more allowed values for the set type and a default value for the set type; storing the set type; receiving one or more second user inputs for creating a first product master class, wherein the first product master class is an electronic database object that represents a first type of product that is for sale and the set type represents the attribute of the first type of product, and wherein the second user inputs associate the set type with the first product master class; storing the first product master class; receiving one or more third user inputs for creating a first sales order class, wherein the first sales order class is an electronic database object that represents a first type of sale for one or more products, and wherein the third user inputs associate the set type with the first sales order class and specify that the association of the set type with the first sales order class is dependent on the set type being used by a product master class of a type of product that is purchased during the type of sale represented by the first sales order class; storing the first sales order class; receiving a first user request to create a first sales order instance for the first sales order class, wherein the first sales order instance is an electronic database object that is an instance of the first sales order class and represents a sale of one or more products that have the first type of product represented by the first product master class; determining, in response to receiving the first user request, that the association of the set type with the first sales order class is dependent on the set type being used by the first product master class; determining, in response to determining that the association of the set type with the first sales order class is dependent on the set type being used by the first product master class, that the first product master class uses the set type; applying, in response to determining that the first product master class uses the set type, the allowed values and the default value for the set type to the first sales order instance; and storing the first sales order instance.