Database Summary of a Summary

When a database which is the result of a summary of another database is again summarized, the minimum and maximum values in the 'second summary' are the high and low values of the base values of the "first summaryā€¯.

In the following illustration, the original database was collected on a 15-minute interval for a week. This database is then summarized to an hourly interval. In the resulting database (top, center), there are field values averaged over an hour, and maximum/minimum values which are the high and low points of the 15-minute average data.

If this database is again summarized, the average data of the first summary provides the basis for the resulting database. (Note: we do not take a max of a max or a min of a min). The resulting "second generation" summary (top, right) contains field values that are averaged for the day and max/min values that are the high and low points of the hourly average data.

The data could have been summarized directly from the original database to a 1-day interval. However, the resulting database (lower right) would contain daily averages for the fields and max/min values which are the high and low points of the 15 minute average data.

The maximum and minimum fields can also be used when a database is summarized into SQL and Enscribe databases. New fields are created in the DDL file and the SQL catalog to accommodate them.

Provide feedback on this article