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In this first chapter you installed MSDE, the sample Northwind database, and Microsoft SQL Server Books Online. You learned about authentication modes and saw how to connect to an MSDE database with osql and with Visual Studio .NET’s Server Explorer.

You’re now ready to develop a simple application against the Northwind database. You’ll do that in the next chapter.

In this chapter you built a simple application without looking in detail at how the code works. Instead, you relied heavily on the rapid application development (RAD) features of Visual Studio .NET. With just a few clicks and a minimal amount of coding, you created some quite powerful functionality. As you worked through the chapter, you learned the following:

You’ll learn much more about ADO.NET components starting with Chapter 4, but before you dive in, you’ll look at the most important tool in the database application developer’s toolkit, the international standard database language SQL.

In this chapter you saw how to use SQL to perform the four most common tasks against a database: SELECT, INSERT, UPDATE, and DELETE. You also looked at how to use comparison and other operators to specify predicates that limit what rows are retrieved or manipulated. Finally, you surveyed the SQL data types and saw how they map to VB .NET and .NET types.

In the next chapter, you’ll start looking at ADO.NET and its components, but that doesn’t mean this chapter contains all the SQL you’ll need for this book. Once you’ve come to grips with enabling these simple SQL elements within your .NET applications, you’ll return in Chapter 12 to learn more SQL and database design techniques.

In this chapter, you saw why ADO.NET was developed and how it supersedes other data access technologies in the .NET Framework. We gave an overview of its architecture and then focused on one of its core components, the data provider. You built three simple examples to practice basic data provider use and experience the uniform way data access code is written, regardless of the data provider. Finally, we offered the opinion that conceptual clarity is the key to understanding and using both data providers and the rest of the ADO.NET API.

In this chapter, you looked at connections using various data providers. You learned about connection strings and connection string parameters, and you saw how to open and close connections.

You examined different security options for SQL Server and other data sources and also saw how to display information about the connection after it’s established, using the properties of a connection.

You saw how to handle exceptions generated by connection errors and learned to close the connection in the finally block of the exception handler to ensure that the connection is closed in all cases.

Finally, you looked at specific examples of connecting to different data sources, including the following:

In the next chapter, you’ll look at ADO.NET and see how to use them to access data.

In this chapter, you learned the following:

In the next chapter, you’ll look in more depth at data readers, which you created in some of the examples in this chapter with a call to ExecuteReader. Data readers give you the results of a SQL query that returns more than one item of data.

In this chapter you learned how to use data readers to perform a variety of common tasks, from simply looping through single result sets to handling multiple result sets. You learned how to retrieve values for columns by column name and index and learned about the methods available for handling values of different data types. You also learned how to get information about result sets and get schema information.

In this chapter, you learned the basics of datasets and data adapters. A dataset is a relational representation of data that has a collection of data tables, with each data table having collections of data rows and data columns. A data adapter is an object that controls how data is loaded into a dataset and how changes to the dataset data are propagated back to the data source.

You studied techniques to fill and access datasets, how to filter and sort data tables, and noted that though datasets are database-independent objects, disconnected operation isn’t the default mode. You learned how to propagate data modifications back to databases with parameterized SQL, how the issues of simultaneous user access may affect the way you write code, and the data adapter’s UpdateCommand, InsertCommand, and DeleteCommand properties. Finally, you saw how command builders can simplify single-table updates and how using typed datasets combine data with the XML schema, which defines it to make multiple-table access easier as long as those tables don’t change themselves in the meantime.

In the next chapter, you’ll start working with form-based applications, as we’ve now covered the basics of database interaction in .NET and it’s time to leave console applications behind. You’ll learn how to use the data you’ve queried for by binding it to controls and that these techniques apply equally to Windows Forms and Web Forms.

In this chapter, we discussed various ways to fetch data automatically from an external data source, be it an array, a database, a dataset, or any data structure capable of storing and retrieving data. You also saw how Windows Forms controls offer built-in support for binding to data sources and retrieving and modifying them. The main topics covered in this chapter were as follows:

In the next chapter, you’ll meet the Web equivalents to a lot of these controls, as you look into ASP.NET and the world of Web Forms.

In this chapter we demonstrated how powerful ASP.NET, and in particular the Web Forms DataGrid control, are for online database applications. Using just a small amount of code, you wrote an application that lets you select, edit, delete, update, and sort rows in a data grid. You also saw how to control rendering of data using bound columns and how to use data binding expressions inside template columns.

Along the way you learned some of the differences between Web Forms and Windows Forms programming. You’ll build on what you learned in this chapter when you study validation controls and ASP.NET data input next.