14. A computer program product, comprising: a non-transitory computer readable storage medium having computer readable program code embodied therewith, where the computer readable program code when executed on a computer causes the computer to: configure a principal model to facilitate automatic generation of at least one resource for use by a computer-executable application, where the principal model comprises a plurality of classes, references, attributes, and associations between any of the classes; identify at least one model item required for a task that is absent from the principal model; instantiate the absent model item in a decoration model that operates with the principal model to augment operational functionality of the principal model, where the decoration model comprises a class, a reference, and an attribute for any corresponding one of the plurality of classes, references, and attributes of the principal model, where a created reference is associated with a key that contains information about a source attribute and a target attribute of the key in the decoration model; and store both of the models within a memory.
18. The computer program product of claim 14 , where the computer readable program code when executed on the computer further causes the computer to provide write access for an object that is created via the decoration model, using a class that is a derived subclass, comprising setting a “type” attribute value according to a subclass lookup value, where the type attribute value is persisted with persistent schema of the principal model such that when the object is subsequently accessed, the object is assigned to the derived subclass.