Retrieve the additional subject field from the database

[torontoxx]

Hi all!
I"m using Neurotechnology Biometric SDK 10.0 (trial) and SQLite as the database engine. I need to store the additional fields (like age) in the database. In order to enable this custom data support i specify a CustomDataSchema property in NBiometricClient:

Code: Select all

NBiometricClient biometricClient;
biometricClient.SetCustomDataSchema(NBiographicDataSchema::Parse(N_T("(Age int)")));


Where: "Age" - the column name, "int" - the additional field type.
To enroll subject with the additional field with name "Age" to the database i"m using a SetProperty method in NSubject:

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   NSubject subject = <...create subject...>
   NLAttributes attributes = <...get age value...>
   subject.SetProperty(N_T("Age"), attributes.GetAge());


All works fine, the subjects with the additional field with name "Age" are enrolled to the database. But how can i retrieve this additional subject field from the database? I tried the next approach (but it does not work):

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NArrayWrapper<NSubject> list = biometricClient.List();

for (NArrayWrapper<NSubject>::iterator it = list.begin(); it != list.end(); it++)
{
   if (it->GetProperties().Contains(N_T("Age")))
   {
      NInt age = it->GetProperty<NInt>(N_T("Age"));
      cout << "      Age: " << age << endl;
   }
}


But this approach does not work: NSubject GetProperties method return no any age property.
My question is: how can i retrieve the additional subject field (like age) from the database?
Thanks a lot!

[MartynasV]

Hello torontoxx,

"biometricClient.List();" only returns subject's ids that are in database(no other data).

You need to perform Get() method to retreive additional subject's data:

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                  NSubject subject = new NSubject();
                  subject.Id = "UniqueSubjectId";
                  status = biometricClient.Get(subject);
                  // Retrieve custom properties, template

[torontoxx]

Hello torontoxx,

"biometricClient.List();" only returns subject"s ids that are in database(no other data).

You need to perform Get() method to retreive additional subject"s data:

Hello MartynasV, many many thanks!
Does it mean that every time a Get() method is called, a SELECT query (like: "select * from database where SubjectId=...") is made to the database?

[MartynasV]

Does it mean that every time a Get() method is called, a SELECT query (like: "select * from database where SubjectId=...") is made to the database?

Yes.

[torontoxx]

Does it mean that every time a Get() method is called, a SELECT query (like: "select * from database where SubjectId=...") is made to the database?

Yes.

Thanks a lot!