Definition of context for specifying uniqueness of identifiers and context-based identifier mapping

摘要

Systems, methods, and apparatus, including computer program products, providing unique identifiers for data-bearing digital objects. Scheme-based definition of uniqueness contexts and scheme-based mappings between identifiers are described. A method of one aspect includes generating a first object identifier for a first object of a first object type on a first system, the first object identifier having an identification context. The identification context includes a first system identifier or one or more second object identifiers of one or more respective second objects. The method further includes providing the first object identifier with the identification context to identify the first object uniquely. A method of another aspect includes defining an equivalence mapping between first identifiers with respective first identification context values and second identifiers with respective second identification context values; and using the equivalence mapping to map an identifier for one object to an identifier for another semantically equivalent object.