A. The Medical Data Meta Model

The data modeling tool is the application used for defining the previously-discussed EHR medical data model shown in 4 and to create tables in the database. It is used for defining parts of meta model and to prepare input for the generator tool that generates tables in the database and related classes and forms used in further development process.

The model created by the data modeling tool can be saved as an XML file and updated later. Currently, tool supports only databases supported by Entity Framework but it can be easily adapted for use with any database supporting object linking and embedding (OLE). In that case user should define parts of its data object model using external tools. Before the table generation process starts, the user has to enter a few necessary parameters (e.g., OLE connection settings) and to select tables that are related to the base medical record and the base medical document. After this, the user can start specifying the structure of the new medical records and documents, including the corresponding elements/fields and data ranges. When this definition process is finished, the user can run the table generation process. This process generates new tables in the database and saves the model in an XML file. Once the data model is mapped into the database, it can be used by our MIS. The created model can be updated later and the related tables will be reconstructed.

An additional feature of the data modeling tool is creation of a model from a specific database. When the user specifies OLE connection settings, the medical record base table and the document base table, our tool examines the database structure and automatically creates the corresponding EHR model. The tool can automatically resolve situations when changes are detected only on one side (in the database or in the model), but when changes are found on both sides, the tool will prompt the list of changes to the user and offer her to merge the two versions. The user can choose to use the model version, to use the database version, or decide item by item what changes should be accepted.

Figure 7. EHR Meta Model Structure

Figure 8. Generator tool – customization form