Building a Database for Dynamic Applications in Macromedia DreamWeaver MX 2004
- Understanding the Structure of a Relational Database
- What Is Involved in the Database Design Process?
- A Brief Introduction to Access
- Building Our Access Database
- Understanding the Limitations of an Access Database
- Expanding Your Database Vocabulary
- Summary
This chapter is from the book
This chapter is from the book
This chapter is from the book
Building a database from scratch is no easy task and building a database to use with a Web site, intranet, or extranet raises additional issues. The goal of this chapter is to walk you through the process of building a database that we can later use when developing our intranet application. The chapter will also introduce you to Microsoft Access, a relational database management system, and help you identify and avoid potential pitfalls that can arise when developing for the Web.
By the end of this chapter, you should be able to do the following:
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Understand the structure of a relational database
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Follow the six steps of the database design process
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Be familiar with building tables and creating relationships using access
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Understand the potential limitations when using Microsoft Access
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Have an expanded database vocabulary
Web Applications, Intranet Applications, and Extranet Applications
In Chapter 2, "Choosing Your Application Type," we spent the entire chapter examining the differences between Web, intranet, and extranet applications. One thing they all have in common, however, is this: each relies on the technology that fuels the Web. For this reason, in this chapter and those that follow, we're going to lump them all together by referring to them as Web applications.
Understanding the Structure of a Relational Database
Databases come in all shapes and sizes, and they range in size and complexity from a simple alphabetized box full of recipes to the most complex back-end relational database for an eCommerce site. For the most part, however, when we use the term database with regards to business and technology, we refer to objects created by database management systems—like Microsoft Access or SQL Server—that are installed on our home or work computers. We use these databases to store a wide variety of data such as employee information, business transactions, and product inventories.
Applications such as Access or SQL Server build their databases based on the relational model, where each database is comprised of tables that are uniquely named. Each table is then made up of records (commonly referred to as rows) and fields (also called columns) of related information. When retrieving data from a relational database, the system cares only about the data that is stored in each record; non-relational systems, on the other hand, not only consider the data but also the structure of the database, making the process of retrieving results much slower.
For example, suppose your relational database has a table similar to the one shown in Table 3.1 that stores the names, usernames, passwords, and login information for each employee in your company.
Table 3.1 An Example of aTable in a Relational Database
|
LastName |
FirstName |
UserName |
Password |
LastLogin |
|
Johnson |
Fred |
johnsonf |
happyday |
03/15/2003 |
|
Jackson |
Sara |
jacksons |
plowdown |
02/11/2003 |
|
Martin |
Eva |
martine |
dailyend |
03/12/2003 |
|
Bellows |
Dan |
bellowsd |
duster |
03/11/2003 |
Because the relational model relies only on the value of the data itself, you could easily ask the system to find all the employees who have not logged in for more than 90 days.