| Description |
The computerized patient record is one of the most important and difficult problems in medical informatics. Relational database management systems have exhibited serious drawbacks when used to implement computerized patient records. First, representing the complicated hierarchy in medicine with relational database tables is very cumbersome. Second, binary data such as image and sound cannot be manipulated directly in relational databases. Third, the data types in Structured Query Language are limited and not extensible. But a potential problem with object-oriented databases when used for clinical data in the proliferation of object classes. An objected -oriented patient lifetime data repository has been designed and implemented using ObjectStore ™, which is an object-oriented database management system. The conceptual basis of this data repository is the Event Definition Model, in which every entity in the real world in modeled as an object type. An event occurs when tow or more intities interact with one another. In the data repository, everything is stored as an object, which encapsulates both the data and the methods for data manipulation. The major object classes of this data repository are CPatient, CEncounter, CCompositeEvent, CAtomicevent, CObservation, and CValue. The proliferation of classes is avoided through the use of data validation. The object-oriented database is compared with its relational database counterpart in terms of query response time. It is found that the object-oriented databases favor single patient related queries and performs as well as it counterpart on population based queries. It is also found that accessing data in objects through indirection and dereference is a serious performance degrader of the object-oriented database when extensive data are displayed, and joining tables a serious performance degrader of its counterpart. |
