Import Task Set Virtuals in Record-by-Record Computations
Suppose a table has a number of columns with computed values, and records in it are processed by an import task. (Computed values can theoretically be extracted from other tables, but because this takes time and the computed values are often re-used, they are stored in a separate field for performance reasons.)
You can use import task set virtuals to hold computed values for the currently imported record.
The standard in USoft technology is to compute values using corrective constraints. In batch jobs, however, you can also use virtuals to compute the eventual values.
Another aspect of these computed values is that in many instances, these values are always produced by batch processing and never during online processing. If you implement the computations in constraints, these are checked unnecessarily during online processing.
You can get record-by-record commit and default error reports even if you want to compute values in EXISTING data. Export the data, then import them (export-for-import strategy). During import, compute the values.
To use import task set virtuals for record-by-record computations:
These import SQL statements typically have the form:
UPDATE <driving import task set>
SET <import task set virtual> =
FROM <database table>[,<database table>...]
WHERE <join with current import record>
INSERT INTO <database table>
SELECT <all columns>
FROM <driving import task set>