Minh,
That example is set up to show how a new record could simultaneously be checked against a seeded database using a supplied list of matchcodes. The existing seed records' key files were built and locked, so end users could run the sample without stepping on each others session.
If you are looking for a more practical method of real time lookups, see the DQT|MatchUp|Samples|sqlserver|mdTriggerExample. This uses the Hybrid deduper, and allows you to compare an incoming key to existing keys (and therefore records) without having to worry about the keyfile, because you store the keys right in the database - you have more control over the keys.
Please contact me with any questions.
Tim Sidor
Melissa Data Corp. | 22382 Avenida Empresa | RSM, CA 92688-2112
tim@MelissaData.com | T: 781-545-7300 | F: 781-545-7717