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SUMMARY 865

Summary

In this, the last chapter of Part IV, you learned about the Multiple Document Interface (MDI), which allows you to write applications that open multiple documents. An MDI application consists of a MDI form, which hosts a number of MDI child forms. Each MDI child form contains a document. The documents are usually of the same type, but if your application can handle multiple document types, the MDI form should be able to host all the document types.

The MDI child form is equivalent to the main form of a SDI application, like the ones we explored in previous chapters. This form contains the code that provides most of the functionality of the application. The MDI form is the container for the child forms and contains a simple menu. Everything else, including the main menu of the application, resides in the child forms.

This chapter concludes the code of the Visual Basic language. In the next part of the book, we’ll look into database programming, and in the last part of the book we’ll explore Web applications.

Copyright ©2002 SYBEX, Inc., Alameda, CA

www.sybex.com

Copyright ©2002 SYBEX, Inc., Alameda, CA

www.sybex.com

Part V

Database

Programming

with VB.NET

In this section:

Chapter 20: Databases: Architecture and Basic Concepts

Chapter 21: Building Database Applications with ADO.NET

Chapter 22: Programming the ADO.NET Objects

Copyright ©2002 SYBEX, Inc., Alameda, CA

www.sybex.com

Chapter 20

Databases: Architecture and

Basic Concepts

In the fifth part of the book, we’ll explore databases. In this chapter, you’ll learn the basics of databases: how they store data, how to update a database, and how to retrieve the information you need from a database. In the following chapters, you’ll also learn how to develop applications that access databases. The topic of database programming could easily justify another book of this size, and there will be many fine books on database programming in the bookstores. The database-related topics discussed in this book were chosen to help you get started with database programming. I’ve selected topics that will help you master basic concepts of databases and ADO.NET, rather than attempt to touch on a large number of topics.

ADO.NET is the data-access mechanism of Visual Studio .NET. In short, it’s a class that provides all the members you need to access and manipulate a database. It’s the most complicated class, because it exposes a large number of members and performs very complicated operations. We’ll have a lot to say about ADO.NET in the following chapters. In the meantime, we’ll start with something less exciting, but equally important.

In this chapter, we’ll look at the basic concepts of the relational model and the Structured Query Language. This chapter isn’t about VB, and you can skip it if you’re familiar with databases and SQL. Because I can’t assume that all readers are comfortable with these topics, I’m including a chapter that will help readers understand the foundations of database programming. You may have watched demonstrations of Visual Studio where someone establishes a connection to a database, drops a few objects on the form, sets some properties, and builds an application for browsing, or even editing, a table almost automagically. However, you can’t expect to go far on the visual tools alone. You must understand how data are structured in databases, how they’re retrieved, and how you update a database.

Step-by-step instructions are fine for building menus or other simple programming tasks, but not nearly adequate for learning database programming. Databases are based on certain principles, and the more you learn about their structure and the mechanisms for manipulating them, the easier it will be for you to follow the material in the next few chapters, as well as continue beyond the material of the book on your own. In the following chapters, you’ll see how to write code that manipulates databases using the objects discussed in this chapter, so the information presented in

Copyright ©2002 SYBEX, Inc., Alameda, CA

www.sybex.com