Wednesday, February 22, 2012


Work is now completed on version 0.6 of GEDCOM-DDL. This is a transformation of the platform independent GEDCOM-UML model, into a database model along with SQL DDL for creation of a SQLite 3 database. This new model is cast in database terminology so it shows tables instead of classes and keys instead of associations. The versions of GEDCOM-DDL and GEDCOM-UML are both 0.6, because I hope to keep the two models in-sync.

Earlier, I posted an analysis of the file size limitations of ezGED Viewer. Now that I have a database schema for storing GEDCOM file contents, I hope to overcome the input GEDCOM file size limits. The size of a SQLite database file will only be limited by the file system in which it is stored. For the FAT32 file system, used on common SD cards, this limit is 4 gigabytes -1.

Friday, February 3, 2012


More progress has been made with the GEDCOM-UML, requiring a version bump to 0.6. The main improvements are:

  • fields with explicit lengths now use the char[n] type (where n is the array size) rather than String
  • documentation has been added to all classes and class members 
  • "tag context" entries have been added to all members to provide  references back to the GEDCOM tag sequence which contributes the member's value

There is still room for more improvement, such as adding some additional types for dates and ages, and enumerations for languages, pedigree linkage types and status, as well as LDS ordinance status values. These are currently represented as char arrays.

Work is far enough along, that I will be turning my attention to the corresponding physical data model for a database schema. Stay tuned ...

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