Principles of a Central Database for System Interfaces during Train Development

Abstract: This thesis has developed a database solution for storage of interface data which are to different systems in a train, the interface data is used in the design of data communication between different systems in the vehicles. The database solution has focused on following problems: revision control of project related data, consistency of interface data between documentation and database, the possibility to roll back the database to an earlier revision, and the possibility to extract delta documents between two revisions in the database. For demonstration of the database solution, a user interface program has been created which communicates with the database. Revision control of the database has been solved by dividing the project related data into three sections: one approved, one modified, and one revised section. The approved section always contains the latest approved data and thereby the ability to read data even though it is subject for a revision at the moment. The modified section contains data that are currently being changed.  Obsolete data are stored in the revised section. To aviod inconsistency of interface data which are stored in both Word documents and in the database, the data is extracted from the database and inserted into tables in the Word documents. The Word documents contain bookmarks where the tables shall be inserted. Algorithms for rolling back the database to an earlier revision, and to extract delta documents were created. These algorithms are not implemented in the user interface program. As a result from this thesis, the interface data is revision controlled and no data is removed from the database during the change process; the data is moved between sections with different flags and revision numbers. Only if the database is rolled back to an earlier revision, data is removed. The functionality to transfer data from the database into tables in Word documents is verified.