Criteria Algorithms Also Define Which Objects To Compare

When the background process selects objects to compare, you can optionally have it call a plug-in to further restrict which objects are compared (table rules are the first level of restriction). We refer to these algorithms as "criteria algorithms".

Criteria algorithms are specified on DB process instructions (just as the table rules are). You'd only need a criteria algorithm if the criteria could not be composed using an SQL statement (if you could compose the criteria using an SQL statement, you'd put this SQL in a table rule).

The comparison process passes criteria algorithms the primary key value of the selected maintenance object. These algorithms simply return a Yes or No value depending on program logic that determines whether the object should be compared. These algorithms are usually defined on a Primary DB process instruction, but there is no restriction.