Now, that we've written all transformation rules, the data from the legacy system is in good shape for our model—we can start with populating it. To extract data from the knowledge session, we'll use Drools queries.
Drools query looks like a normal rule without the
then part. It can be executed directly from a stateful knowledge session for example,
session.getQueryResults("getAllCustomers") or by using
QueryCommand. It returns a
QueryResults object that can contain multiple
QueryResultsRow objects. Every
QueryResultsRow instance represents one match of the query. Individual objects/facts can be retrieved from
QueryResultsRow. Drools queries are a convenient way of retrieving objects/facts from the knowledge session ...