Using Databases in Visual Basic

There are a few different ways that Visual Basic can interact with data stored in a database.

• Use ADO.NET, the primary data access technology included in the .NET Framework, to interact with database-stored content. This is the method used throughout the Library program to interact with its database. ADO.NET is discussed in Chapter 10, "ADO.NET," with examples of its use. I will also introduce ADO.NET-specific code into the Library Project in that chapter.

• Use the "data binding" features available in Visual Basic and Visual Studio. Binding establishes a connection between an on-screen data control or similar data-enabled object and content from a database. Code written for you by Microsoft takes care of all the communication work; you can even drag-and-drop these types of interactions. Although I will discuss data binding in Chapter 10 (because binding is based on ADO.NET), I tend to avoid it because it reduces the amount of control the programmer can exert on user data management. Data binding will not be used in the Library program.

• Extract the data from the database into a standard file, and use file manipulation features in Visual Basic to process the data. Hmm, that doesn't seem very useful, but I have actually had to do it, especially in the old days when some proprietary databases could not interact easily with Visual Basic code.

• Each time you need some of the data, tell the user that somehow the data has been lost, and that it must be reentered immediately. If you have ever been curious to know what the inside of an unemployment office looks like, this could be your chance.

If you are a former Visual Basic 6.0 (or earlier) programmer, you may think that your knowledge of ADO will translate directly into ADO.NET development. Ha! You couldn't be more wrong. Although the two data technologies share a partial name, the code written to use each method varies considerably. I will not discuss the older ADO technology at all in this book.