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GENTECH-GDM Background

Version 1.0 of the GENTECH Genealogical Data Model was released August 21, 1998 as an RFC (Request for Comment) at the Federation of Genealogical Societies Conference. On May 29, 2000, Version 1.1 of model was released. This is the current specification which is available at the GENTECH website.

The data model uses ERD, Entity Relationship Diagrams for its description. The terminology is heavily influenced by relational database concepts. Much of the early work on the model took place in 1996, before UML (Unified Modeling Language) was widely adopted as the standard object modeling language.

The purpose of the model was to "define genealogical data for the purpose of facilitating data exchange among genealogists." A logical model was created which serves to describe the conceptual relationships of genealogical data but not an implementation model from which software could be constructed.


I have recast the GENTECH-GDM in UML terms.
The by-product of this analysis is a GENTECH-GDM Reference Model which is available in PDF format. It describes classes of the Evidence, Administrative, and Conclusional sub-models and has detailed class diagrams for each sub-model. This is a "strict" interpretation of the original GENTECH Entity-Relationship model. The entity names and attributes are carried over to the UML classes. A separate section extends the model with a suggested sub-model for Dates.

GENTECH-GDM Reference Model (in UML): gdmref-01.pdf (920 kb).

GDM Sandbox

Development is underway on a "GDM Sandbox" MS-Windows application. It will use an XML-file for serializing/deserializing the contents of a GDM project. The plan is to implement each submodel as a separate stage:

  • the Administrative submodel first
  • then the Evidence submodel
  • finally the Conclusional submodel

Once the major sub-models are in place, import/export interfaces to some other file formats, as well as other features can be added. As stages are completed, they will posted here for feedback and comment.

The current draft of the GDMUML specification is available through this link: GDMUML-0.4.
The 0.4 revision describes the classes of the Evidence, Administrative, and Conclusional submodels and includes class and object diagrams. (This document will evolve to become the implementation specification for GDM Sandbox.)