Demographic Surveillance System Database

Abstract: This examination work presents a proposition of a conceptual design of a demographic database for CIDS in Nicaragua. Furthermore, an implementation of this database is described. Finally a description of a method to transfer data from the current database to the new is given, together with a smaller implementation. CIDS – Center of Investigation of Demography and Health is located in Nicaragua, Leon, and works with collecting statistics about the population. Their main areas of work is statistics about pregnancies, infant mortality, public health, levels of education, poverty index, internal migration, immigration and emigration. All this information is stored and processed in a database system, which is created in Microsoft Access. The system has been developed during a long time, and gradually adapted when new requirements has been added. Today it is a complex database with very much and diverse types of information, from where researchers and others can get historical data spanning from 1993 until today. CIDS is unique in Nicaragua, there is no governmental or communal organization which collects this type of statistics, which means that CIDS work is very important in order to get a correct picture of the population of Nicaragua. The current database suffers from the ‘patch and paste’ syndrome, which means that new functionality and tables has been added during its long existence, and fixed and patched so it will work with the current design. The result of more than ten years of fixing and adding is a quite fragile design, which is hard to understand and maintain. Lots of errors have been inserted as well, due to a bad user interface. Organizational mistakes have made some data disappear. Misinterpretations have caused some data to get entered wrong, which in the end has rendered the data unusable. The lack of updated documentation has meant problems when a person with knowledge about the system has disappeared from CIDS, so later changes and updates of the database’s design has been difficult, and mistakes has been done. Our examination work’s main point has been to present a new database design which can replace the current. This new design should solve most of the current problems and also simplify future changes of the design. It was of most importance to also present a method to transfer the existing data from the current database to the new one, in a completely safe way, where we could show that no data and no relations were lost in the process. There should also be a user interface, where new data could be entered and changed, and an interface for collecting and present the statistics to the researchers which will use it in their work. Our examination work is a continuation of a work that Nils Assarsson and Tommy Ljunggren did in 2003 [5], where they identified the shortcomings and problems existing at CIDS in their database system and their way of collecting the statistical information.