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Lesson 4 Databases and Web sites
Objective Explain the characteristics and protocols of back-end Web databases.

Databases and Websites

The different database models you just learned about each have their own benefits and drawbacks. Selection of a database model for a particular project will depend on what your clients have identified as the major purposes that their database will serve.
Web sites of large organizations almost always have some kind of database features included. These database-driven Web sites are characterized by:
  1. Mechanisms to display data from the database
  2. Queries of the database using criteria from the user
  3. The ability to send formatted data from the user for storage in the database
E-Commerce sites are prime examples of database-driven Web sites. The data in an e-commerce site must be available to retrieve, display, and store data for commerce to occur. In addition, the data must be checked for required data and format, and security and integrity during its transport.

How do they communicate?

In order for a database to be an integral part of a Web site, there needs to be a permanent mechanism for communication between the Web server and the database server. There must always be a way for the client machine to communicate with the Web server. The following FlipBook illustrates the communication process.

Database Website Communication

Database Access Protocols

Protocol Description
ODBC The most common general database protocol is Open DataBase Connectivity (ODBC). This technology was developed jointly by IBM, Microsoft, and a number of other manufacturers in the late 1980s to make it easier to interoperate between their various database products. The snap-in components of ODBC are know as ODBC drivers, and they can be found or bought for virtually every common database platform. ODBC is slower than newer technologies such as OLE-DB, but has the widest support of both databases and applications that can use ODBC to access a database.
JDBC Sun released JDBC, the Java equivalent of ODBC, shortly after Java was released. This is the connection method of choice for Java applications, but drivers exist for fewer databases than with ODBC.
OLE-DB Microsoft's newest technology for database access is OLE-DB, which is part of their entire enterprise COM architecture. The snap-in components for different databases are known as providers and they are far more sophisticated than the ODBC and JDBC drivers. The support for databases is quite limited, albeit to the most popular database platforms (MS-SQL Server, Oracle, and the like). This is probably the highest performance method for accessing a database outside of the native database drivers, but it's also currently limited to the Windows NT platform.

In the next lesson, you will learn the importance of data modeling