how to save my biometric fingerprint scanner files(.Fpt), to my sqlserver database and how to retrieve it?

create the VARBINARY datatype in your SQL Server and save like this (just a snippet)

byte[] fingerprintfile = my.computer.filesystem.readallbytes("C:\myfinderprint.fpt");
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command().parameters.addwithvalue("@FingerPrintFile", fingerprintfile);