Research in the domain of computer-based patient records had always faced the conflicting demands of efficiency for the practicing physician and suitability of the record contents for data analysis in view of decision support, research, and quality assessment. Interface and contents pose different demands on the data model underlying the record. The challenge is to combine the most suitable model for data representation with the interface that best fits the clinical setting. ORCA (Open Record for CAre) provides a solution by making the distinction between domain dependent and domain independent data and letting domain dependence be decisive for the choice of model. Interactive definition of custom-views provides interface flexibility for domain dependent data. Views on domain independent data need not cope with the limitations of multiple table views in relational DBMSs. A standard set of single table queries can support recording of domain independent data, irrespective of the clinical setting.