HPCC-10222 Perform proper field validation.

Signed-off-by: Rodrigo Pastrana <Rodrigo.Pastrana@lexisnexis.com>
Merge pull request #4992 from rpastrana/HPCC-10222-field-validation

HPCC-10222 Perform proper field validation.

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>