Abstract: A structured data management system which provides services concerning a structured electronic data object. In this system, a structured data storage unit stores a plurality of structured data objects associated with each other. Each structured data object can be represented as a tree structure constructed by a plurality of data elements, or nodes. Further, the individual nodes of a tree structure are associated with their respective process scripts. Through an input/output interface unit, a message addressed to a certain destination node arrives. Upon receipt of the message, a structured data processing unit identifies the destination node by tracing the tree structure of a particular structured data object where the destination node resides. The structured data processing unit then executes a process script associated with the destination node being identified.

Abstract: A structured data management system capable of easily changing the definition of a logical structure and controlling semantics described in data adapted to the defined structure as intended by persons who have defined the logical structure. A contents model defines an internal structure of a contents description. The contents description describes data to be managed according to the contents model. An operation description is coupled to the contents model and manipulates data in the contents description depending on the structure of the data in the contents description. The operation description functions to define semantics of each element of the structure defined by the contents model. An operation description executing unit executes the operation description coupled to the contents model. A structure managing unit verifies and manages the structure of the contents description according to the contents model.

Abstract: For warranting a validity of data recorded on a medium such as a rewritable magneto-optic disk etc, when registering a plurality of documents (n, n+1 . . . ) on the same recording medium, an n-th authenticator obtained by executing an encrypting process of data of the n-th document is recorded together with the n-th document data, and, when registering data of the (n+1)th document, an (n+1)-th authenticator is generated by executing the encrypting process of the n-th authenticator and the (n+1)-th document data as the (n+1)th authenticator.

Abstract: In an information management system, individual entity information items related to one another are assigned unique identifiers. A smaller number of pointers are used to define high, low, front and rear-rank links among the entity information items. In an entity management table are placed records having a pointer to an entity information item and an identifier of the entity information item. In a structure management table are placed records representing types of the entity information items and having pointers to high, low, front and rear-rank records. There is further provided an identifier management table that relates the types of the entity information items to the identifiers. Use of these tables permits data retrieval in four directions of upward, downward, forward and rearward.

Abstract: A structured database system includes a first unit for obtaining a structure definition frame of a document showing a structure of the document, and a second unit for storing body data of the document in a database together with the structure definition frame.