Multiple-computer data processing system and method with time-versioned data storage

摘要

A data processor comprises a number of databases for storing records and a plurality of user systems capable of accessing the databases. The user systems each include a datastore/application environment instance with which users can interface. Host systems may include more than one instance. The datastores contain time-versioned views of records. The data processor is operable in at least two modes, a normal operation mode in which an evaluation in response to a user enquiry can be carried out using records relevant to a current viewpoint time and time span, and a recovery operation mode in which records relevant to a viewpoint time and time span for a previous evaluation are accessed and used to exactly reproduce the previous evaluation.