Type system for building extensible business applications

摘要

A platform (referred to herein as Extensible Application Platform, or XAP) for developing extensible business applications. In one set of embodiments, XAP can include an Extensible Markup Language (XML) based application model that is designed to support a high degree of application extensibility. For example, the XAP application model can support declarative definition of application semantics, separation of application data and metadata, and a flexible type system that allows constraints and calculations (e.g., XQuery constraints and calculations) for a data object instance (e.g., an XML document) to change over time. In certain embodiments, the XAP application model can be implemented via a server-side database/application engine that is configured to interoperate with a spreadsheet-like, client-side user interface. Using the spreadsheet-like UI, a non-programmer can build, customize, and run an application workflow that operates on top of a shared database like a traditional business application.

主权项

1. A computer-implemented method comprising:
storing elements that describe element instances that can occur in a collection of hierarchical data objects; wherein said collection of hierarchical data objects includes a hierarchical data object that contains particular element instances;
wherein for each particular element instance of said particular element instances, a particular element of said elements that describes said particular element instance defines one or more constraints, each constraint of said one or more contraints being active or inactive at a particular point in time for said each particular element instance; and at a first point in time, validating the hierarchical data object against the elements, wherein validating the hierarchical data object includes:
for a certain element instance of said particular element instances:
from among constraints defined by a certain element of said elements that describes said certain element instance, determining a first set of one or more constraints that are active for said certain element instance; andin response to determining the first set of one or more constraints that are active, validating said certain element instance based on the first set of one or more constraints.