you first register a fingerprint then store that binary value

later when a user needs verification you scan the fingerprint again and use the function provided by DigitalPersona SDK to compare a fingerprint to a registered fingerprint

you cant simply use these values to find in a database as they are never really the same.

we always knew who the user was so we simply compared it to the users registered prints on file.

there are some databases that have specific fingeprint finding features as far as i remember i think oracle is one of them if i remember correctly

if you only have a few records you could simply run through them and check all of them but this also increases the chances of false positives