To produce a continuous query for an append-only database, a client defined query first is converted into its minimal bounding non-decreasing monotone (hereinafter referred to as "monotonic increasing" query. This monotonic query, in turn, is converted into an incremental query, The resulting monotonically increasing incremental query then is installed on the database as a stored procedure that takes two date/time parameters (hereinafter referred to as "time" parameters), one of which (.tau.) identifies the last time the procedure was executed, and the other of which (t) identifies the current time. All database records are timestamped as of the time that they are entered into the database. Thus, in operation, more or less standard procedure calls periodically invoke each of the stored query procedures, thereby periodically executing the incremental queries over database records that have timestamps spanning successive time slots.

An information retrieval system including a plurality of indices representative of information stored in the information retrieval system and a dynamic lexicon is disclosed. The system includes memory having a database stored therein, the database being logically divided to include the plurality of indices, an information database having information objects stored therein and a dynamic lexicon which includes a plurality of data items and groups of data items that appear in the information database. A predetermined time variable represents the last time the plurality of indices were reindexed. After changes are made to the lexicon, a time stamp is attached to each one of the plurality of changes to the lexicon to indicate when the change was made to the lexicon. At some specified time interval later, the reindexing process is invoked. This process involves selecting a subset of the plurality of changes made to the lexicon after the predetermined time variable, locating all information objects in the information database that are affected by the plurality of changes to the lexicon, reindexing the portions of the plurality of indices representative of the information objects affected by the changes to the lexicon to reflect the changes in the lexicon, and then updating the predetermined time variable to indicate changes to the lexicon have been processed. The foregoing process is repeated until all changes to the lexicon after the predetermined time have been applied to the plurality of indices.

A method and apparatus for providing an historical perspective into a database of information objects through an efficient method and apparatus for versioning information objects stored in a database as well as an index representative of the information objects is disclosed. The latest versions of each one of the information objects and each one of the entries in the index are maintained in the database. Partial earlier versions of each one of the information objects and each one of the index entries are stored with the latest versions. The partial versions contain only sufficient information about the differences between the earlier versions and the later ones so that any earlier version may be reconstructed. Identification tags are employed as unique identifiers for each one of the plurality of information objects and for different versions of the information objects. Through the exploitation of the relative time ordering of generated identification tags, an efficient index representation and method for performing historical queries is provided.

The database is provided with an audit trail for the structure types of the object instances. As a component of an object instance of the database is corrected/changed, the corrected/changed component is substituted for the original component and the original component is linked to the corrected/changed component.

An installation creates a source I/O definition file (IODF), defining a current system I/O configuration, and a target IODF, defining a future I/O configuration. An activate function is initiated to change the system's hardware and software definition to correspond to the target IODF. A compare function compares the source and target IODFs, and creates a Configuration Change Block (CCB) to efficiently drive the change process. A validation function validates that the proposed change is valid, and the change process updates the hardware and software configuration definitions. If the change process is successful, a notification is sent; if not, a back-out process restores the I/O configuration to its initial state.