Generating summary data such as traffic summary information from a plurality ofdata records

摘要

Summary data of some event, such as traffic data for a computer or communications network, is stored in tables having different temporal resolutions. For example a first table may contain summary records of traffic flow at hourly intervals and a second table summary records of traffic flow at daily intervals. The data from a succession of records is summed to determine traffic flow over a requested period of time. The records are selected from the table which has the lowest temporal resolution allowing the requested start time or the end time of the previous record summed in the succession to be matched. The process is repeated until sufficient records have been summed to cover the requested time period. The arrangement reduces the number of records which have to be accessed to cover the requested time period.