Chapter 1:The .NET Foundation 15   System System.Data System.Drawing System.Windows.Forms System.XML An ASP.NET Web Service automatically imports the following namespaces: System System.Data System.Web System.Web.Services System.XML It is possible to import additional namespaces for use application-wide  by right-clicking on the References folder and selecting Add Reference. You will then be able to  import any of the other namespaces that are available. The Base Class Libraries The Base Class Libraries (BCL) are a set of classes, value types, and  interfaces that give you access to specific developer utilities and various system functions. The  preceding section covered how these classes are organized by the system of namespaces that  are in place in the .NET Framework. Now take a closer look at the classes that are provided  in the .NET Framework. All the languages that sit on top of the .NET Framework have equal acces s to all the classes that are contained within the BCL. This actually makes it quite easy to  look at code from another .NET language and understand what is going on in the code. You u se the SQLConnection class in Visual Basic .NET to connect to SQL Server exactly the way you do in C#, although the language semantics are different. Table 1-1 gives a brief description of some of the classes available wit h the .NET Framework. This table is not a comprehensive list of available namespaces. You can  find all the namespaces within the .NET SDK documentation. It is important to realize  that you are not limited only to these namespaces. You can create your own namespaces to  use within your applications, and there will be third-party namespaces on the market tha t are available to use as well. One example of a third-party namespace is the System.Data.Oracle namespace. Table 1-1   Namespace Definitions Namespace Description System Provides base data types and almost 100 classes that deal with situations like exception handling, mathematical functions, and garbage collection. System.CodeDom Provides the classes needed to produce source files in all the .NET languages.