|Adminstrative Divisions of Vietnam Database|
This example was developed for Brian Zottoli to demonstrate how a relational database model could trace the development of Vietnam's administrative divisions as they changed across time.
There are two versions of the relational database of Vietnamese Administrative Divisions. The first is contained in an ACCESS database with associated GIF images, the second is a MySQL implementation (which relies on the same images stored in the previous archive).
The basic idea of the database is to identify each unique administrative division that exists for a particular period of time (the are historical instances, recorded in the vm_inst table). If an admin unit changes, it requires two instances, one as it existed before the time of change, one as it existed after the time of change. Each instance is meant to represent the stable period during which no change occurs.
Each instance can also be associated with a place object (recorded in the vm_po table). The place objects are meant to be the ID numbers of entities which change over time, basically a way of explicitly linking a series of historical instances. In other words, if instances A, B, and C are all related to place object Z, then they are phases of Z. This is a touchy, and not altogether satisfactory way of dealing with modeling historical objects, but there you are! (see Berman, 2006)
There is a comment table (vm_com) which provides a textual comment. In the case used here there is both a GIF image of a map, and a placename (label for the map). The comment table is linked to the instance table (with the vm_cmlk table).
Some search engine scripts are included in PHP, which can connect to a MySQL database. If you want to use them, update the connection and database name info to match the location of the tables. Create table commands and table descriptions are included. Then create a subfolder in the folder where the PHP scripts live called [images] and dump the GIFs there. If you do an [ls] or [dir] on the folder it should look like:
images index.html vm2.php vm_banner.html vm_home.php vm_navbar.html
- Berman, 2006
'Persistence or Transience? Tracking the evolution of places over time with historical GIS'
- CHGIS Data Model
'Data Model for Historical GIS, CHGIS Time Series'
Vietnam Administrative Divisions
BASE 802750AI (C00082) 8-01
Online Map Image
Disaster Mmgt Unit, Vietnam Provinces
Province list and link to images