Aggregating Item Data

Aggregating item data involves identifying constituent items for an Aggregation Measuring Component, calculate item measurement data for the aggregation period, and aggregating that data.

Aggregation of interval measurements is handled by the Aggregate Item Data (D1_​AGGITEM) algorithm. The algorithm performs the following steps:

• It calls the Find Constituents for Items (D1-FICONITEM) algorithm and populates the GTT3 global temporary table with groups of device types (for badged items) and/or service point types (for unbadged items) (see Find Constituents for more details about this process).

• It deletes any constituents from the GTT3 table that do not have 100% coverage for the dates in the aggregation period.

• For each remaining constituent in GTT3, the algorithm calculates measurements for the aggregation period and inserts them into the GTT4 global temporary table by applying the item counts for each group to the item interval (profile) data. If the SPI and UOM are different from that of the Aggregation Measuring Component, the measurements are converted to a common SPI using Axis Conversion.

• It performs aggregation calculations on the measurement data in the GTT4 table, using data source template SQL, extended by the value identifiers defined on the measuring component type of the Aggregation Measuring Component.

• It either inserts or updates the results to the appropriate measurement table (the standard Measurement table, or the Aggregation Measurement table)

• If there is no data for any dates in the aggregation period and previously aggregated measurements exist, those measurements are deleted to indicate the absence of data.

• It updates the Most Recent Measurement Date/Time and Latest Measurement Date/Time values on the Aggregation Measuring Component.