1. A method of implementing a data access control facility, said method comprising: assigning personally identifying information (PII) classification labels to PII data objects, wherein a PII data object has one PII classification label assigned thereto; defining at least one PII purpose serving function set (PSFS) comprising a list of application functions that read or write PII data objects; and assigning a PII classification label to each PSFS, wherein a PII data object is only read accessible via an application function of a PII PSFS having a PII classification label that is equal to or a proper subset of the PII classification label of the PII data object.