Program a Visual Basic XML Database

By Stephen Bucaro

XML is the newest "golly gee wiz" buz word on the net today (well actually "WiFi" is, but that's another story). Basically XML is tags, similar to html tags, that you place around data. Html tags define how to display a Web page. XML tags describe the data contained in the Web page or document. Because XML is a W3C standard, it has found a use in communicating between dissimilar databases.

For efficiency, most databases are stored in binary format and are not human readable without the dbm (database management system). Several times I have lost databases because they became corrupted. I wished I could open the database in a text editor to see what was wrong and possibly make a repair. I like XML because it's human readable ASCII text, not binary data.

There are many books available that teach you how to properly construct an XML document, but there is very little information available about how to do something with XML. In this article I show you how to program an XML database with Visual Basic. I assume that you already know how to program a simple Visual Basic .EXE project. Other than that this article is for beginners.

 For your convenience I have zipped together the Visual Basic source files and the XML document used for this example, which you can download by clicking here

The database that I describe in this article will be a simple flat database. Whereas a relational database contains several tables, along with relations between the tables, a flat database contains only one table. The disadvantage of a flat database is that sometimes data is repeated in the table.

This example consists of two parts, an XML document and a Visual Basic program that is used to browse, search, and edit the XML document. In this article I will be referring to the XML document as the "database". The nice thing about XML is that it is a standard, so you are not confined to reading the database with any specific application. You can read this database with any XML document reader including Internet Explorer or any ASCII text pad program.

The example database contains all the different modes which can be set for a computers display. Each record will contain the fields; resolution, number of color bits, number of colors, and bytes of memory for a full screen. Shown below is one record from the database.

640x480 4 16 153,600