The Web Server Environment - Database Processing: Fundamentals, Design, and Implementation - page 454

Relational Databases:
Oracle Database,
Microsoft SQL Server,
MySQL, Microsoft Access,
IBM DB2 . . .

Native
Interfaces

DBMS

ODBC

Browser

Nonrelational
Databases

O
L
E

A
D
O

D
B

Web
Server

Browser VSAM, ISAM,

Other File
Processors

Browser

E-mail, Other
Document Types

Pictures, Audio,
Other????

Figure 11-15
the role of aDO

adds much more. In particular, ADO.NET facilitates the transformation of XML documents
(discussed later in this chapter) to and from relational database constructs. ADO.NET also
provides the ability to create and process in-memory databases called datasets . Figure 11-16
shows the role of ADO.NET.

The ADO.NET Object Model
Now we need to look at ADO.NET in more detail. As shown in Figure 11-17, an ADO.NET
Data Provider is a class library that provides ADO.NET services. Microsoft supplied ADO.
NET Data Providers are available for ODBC, OLE DB, SQL Server, Oracle Database, and
EDM applications, which means that ADO.NET works not only with the ODBC and OLE DB
data access methods we have discussed in this chapter, but directly with SQL Server, Oracle
Database, and .NET language applications that use EDM as well. ADO Data Providers from
other vendors are available through http://msdn.microsoft.com/en-us/data/dd363565 .
A simplified version of the ADO.NET object model is shown in Figure 11-18. The ADO.NET
object classes are grouped into Data Providers and DataSets.
The ADO.NET Connection object is responsible for connecting to the data source. It is basi-
cally the same as the ADO Connection object, except that ODBC is not used as a data source.

Figure 11-16
the role of aDO.NEt

ADO.NET DBMS

DB

Windows
Applications

Web
Applications

XML Web
Services