ADO.NET Programming in Visual Basic.NET / Edition 2

Introduction

by Bob Howell

Welcome to ADO .NET Programming in Visual Basic .NET. As a fellow VB programmer and developer, I wrote this book for two reasons:

• To introduce the VB Classic (VB Version 6.0 and prior versions) programmer to VB .NET and ADO .NET and take some of the version shock out of the transition.

• To introduce non-VB programmers who have experience in other platforms (specifically Java or C++) to the advantages of database programming with the new .NET platform.

My intent is not necessarily to win you over and get you to switch platforms. That is the job of Microsoft's marketing people. My intent is to show that .NET is a radical departure from previous versions of VB and that it is a first-class tool for serious development.

A Disruptive Release

When I first started working with the beta versions of Visual Studio .NET, I could see from the very beginning that this was going to be a disruptive release, a term I adapted from sociology. In sociology, disruptive innovation refers to the invention of something so revolutionary that it changes the basic rules by which the society functions. The automobile, airplane, and personal computer are all examples of disruptive innovation.

Once the automobile was invented there was no reason to further develop horse-drawn buggies. So by calling VB .NET a disruptive release I mean that Visual Studio .NET is such a radical departure from what most VB Classic programmers are used to that it would require almost complete retraining to bring them to the point of being as productive as they were in their prior VB version. Having programmed in VB since Version 1.0, I remembered what the conversion from VB 3 to VB 4 entailed. That was the last time Microsoft radically changed the language to support 32-bit programming and operating systems such as Windows 95 and NT.

Microsoft also switched from the VB-specific VBX format component model to the new (at the time) OCX OLE-based component model. This caused a lot of consternation and discussion (read whining and complaining) among the programming community. If that seemed difficult, this time is not even remotely as easy. That was a breeze compared to this.

VB .NET

As I worked with Visual Studio .NET, however, I could see that this was much better than what we had in the past. VB Classic had grown from basically a scripting tool to a sophisticated development platform capable of creating line-of-business class systems. It also became bloatware, meaning the package became so large and cumbersome that with each new revision, we had to learn a whole new set of tools and wizards.

In the wider world of programming, VB Classic is an anomaly. It has its own proprietary IDE, its own runtime, a peculiar syntax, and its own proprietary forms package. None of these items works very well with other languages. VB Classic grew out of the early BASICs that came with old microcomputers. I remember Level II BASIC, the language that ran on my old (circa 1979) Radio Shack TRS-80 Model I, also known as the "Trash-80." While it still used line numbers, GoSubs, and Returns, it had the same basic syntax as VB Classic. That language evolved into GW-Basic that came with the original MS-DOS.

We then had Quick Basic, a cheap compiled version of GW-Basic. Then there was the Basic Professional Development System, a fully compiled and linked BASIC language for MS-DOS development. Finally came VB 1.0, which kept much of the syntax, statements, and functions of the older languages to try to win those programmers over to Windows development. If you don't believe that VB Classic evolved from those early languages, you should know that VB 6 still supports line numbers, GoSub, -Return, and GoTo. It also supports On-GoSub, an early form of a Select-Case statement. Microsoft doesn't advertise this, but it does work. Try it sometime. VB Classic has maintained that evolutionary path up until VB .NET.

With VB .NET, we now have a fully object-oriented programming language that rivals other languages, such as Java. The forms package is generic and no longer limited to use with just VB. You can actually pass entire forms across a network connection. While much of the syntax is the same (it is, after all, still BASIC), it has been standardized and brought into conformance with other languages. You no longer pass values into functions by reference as the default. The default is now by value, which is how virtually all other languages do it. Unfortunately, this will make transitioning difficult for many VB Classic programmers. This book is designed to ease that transition, and avoid the mistakes and wrong turns I made while hacking through it myself.

ADO .NET Programming

ADO .NET programming has a special connection with Visual Studio .NET, and we'll see both packages at their best and most powerful in this book.

These two packages—ADO .NET and Visual Studio .NET—are specifically designed to work together. Visual Studio bends over backward to make using ADO .NET easy, and I'll cover the Visual Studio .NET database tools like the Project Explorer, the various data adapter and dataset configuration tools, the query builder, and more in depth. In fact, the natural environment for ADO .NET programming is Visual Studio .NET—and I think you'll agree as you read this book.

If this book is titled ADO .NET Programming in Visual Basic .NET, why do I keep referring to Visual Studio? Well, in the past, VB (and its variants, VBScript and VB For Applications) was the most natural environment for ADO database programming. The other Visual Studio tools (Visual C++, Visual Interdev, Visual FoxPro) could all use ADO, but since ADO was designed around the COM (Component Object Model) architecture, VB was the easiest way to use the package. With the advent of Visual Studio .NET, this has all changed.

Visual Studio .NET no longer uses COM as its underlying architecture. Instead it uses the Extensible Markup Language (XML) and Simple Object Access Protocol (SOAP). (You can still use your old COM objects in .NET, even ADO, but that is outside the scope of this book.) The common language runtime (CLR) interpreter allows all of the managed languages (VB, Managed C++, and C#) to utilize a common set of data types and interfaces so they can all use the same objects interchangeably. In fact, you can write components in C# and use them in VB and vice-versa. So while we will use VB .NET syntax in all of the examples and demonstrations in the book, the principles we are sharing will apply equally to C#.

What's in This Book?

This book covers ADO .NET programming using VB .NET, which means there's a great deal of material to work with: the basics of the ADO .NET object model, Web Services, typed and untyped DataSets, DataAdapters, ASP .NET, and DataBinding. ADO .NET is intended to be the future of data access as far as Microsoft is concerned, and we'll see it all here.

What You Will Need

The short answer is that you will need Microsoft Visual Studio .NET Professional Version or higher. Any machine that will run that will be capable of executing the examples in the book. If you are not sure if your machine will run Visual Studio .NET, the requirements are:

• A Pentium II 300mhz or higher. I have successfully run Visual Studio on a Pentium II 300mhz Notebook. I recommend a faster machine if possible. NO Pentiums or 486s.

• At least 256 megabyte (MB) of random access memory (RAM); 512 MB is preferred. Unless you have access to a server, you will also need to run the Microsoft Database Engine (MSDE) or SQL Server 2000 and Internet Information Server (IIS) services so this memory is not all yours.

• I can't see using a display with anything less than 1024x768 resolution, unless you have really great eyesight. A 17-inch monitor is also preferred.

• A 10-gigabyte (GB) hard drive. Visual Studio .NET fully installed takes a whopping 1.7 GB! You will need to install the Microsoft Developer Network (MSDN) library that comes with it.

• Microsoft Windows NT 4 Workstation with Service Pack 6, 2000 Professional or XP Professional. The IDE will not run on Windows 95, 98, or Millennium Edition Me. (Programs developed for the .NET framework will run on Windows 98 and Me, but you must have NT 4 or higher for development. It may run on XP Home; check with Microsoft on this.

• Access to MSDE or SQL Server 7.0 or 2000. The MSDE comes with Visual Studio .NET Professional Edition. We will not be using the Jet Engine (Microsoft Access). This is because Microsoft Access does not support stored procedures or triggers. You will also need the Northwind database. This comes with the full versions of SQL Server, but when I installed the MSDE, it was not there.

If the entry price of Visual Studio .NET Professional makes you unhappy (the nonupgrade version is about $800), you can get a free 60-day evaluation copy from Microsoft. Or you can get your boss to buy it for you. Just convince him or her that the next big project cannot be done without it! Microsoft will love you and so will I. There is a "Standard" version of VB .NET on the market. It has a really great price, but, unfortunately, it lacks too many features to make it usable for this book.

You will also need some programming experience. It's good if you've programmed in previous versions of VB, but experience with any Basic language will do. If you've programmed in another object-oriented language, even better. Some experience with databases is also desirable. A decent understanding of basic SQL (Select, Update, Insert, and Delete) will help a great deal; we are not going to attempt to teach SQL. We will give you the basics, but there are other great books on SQL. The purpose of this book is to teach you how to use ADO .NET from within VB .NET and that is what we shall do. When you finish this book, you will be well-equipped to begin developing serious business applications in VB .NET.