Patent ID: 7155450

Claim:
A plant information management system comprising: a data logger for interfacing with a plant process device to receive plant process measuring point data in real time, and at a non-uniform rate, said data comprising a plurality of events, each of said plurality of events comprising a time stamp having most significant bits, least significant bits, an event value and a data quality indicator; a plant information database; and a database controller for storing the events in said database, wherein: the database comprises a time-encoded structure which is hierarchical according to time periods of the most significant bits of the time stamps of the measuring point data, with successive hierarchical levels associated with shorter time periods; said time-encoded structure is defined according to a breakdown of bits of the time stamp; the database controller stores each event value in an event object in a value level linked with the time-encoded structure; the database controller stores the least significant bits of the time stamps in the event objects, the most significant bits being encoded in the time encoded structure; the database controller stores each event value as an attribute of an associated event object; the database controller accesses said value level to perform writing by using said time-encoded database structure as an index; the database controller performs time-based data queries by using a time value to drill down through the time-encoded structure to reach at least one selected event object in the value; and the database controller stores the data quality indicator only if it is exceptional.