A relational database model is presented that stores the hierarchical linkages between clinical events with qualifier codes, such that the explicit contextual meaning of an event's attributes is preserved upon retrieval. A retrospective analysis of 302 forms built upon the model showed that 91% of 17,899 data elements requested by clinicians and researchers from 19 clinics were successfully represented, but that 62% were never used more than once. These results reinforce the specificity of clinic-specific databases and the need for unambiguous, explicitly-stored clinical data.