MACROMEDIA COLFUSION MX 7-GETTING STARTED BUILDING COLDFUSION MX Getting Started page 33

About relational tables
In a database, you can organize data in multiple tables. For example, if you manage a database for
the Human Resources department, you might have one table that lists all the information about
employees and another table that lists all the departments:
You have multiple departments for employees, but you would not store the information about the
departments in every employee row for the following reasons:
•
The department information is the same for each employee in a given department; however,
repeating the department information for each employee is redundant. Storing redundant data
takes up more disk space.
•
If the department information changes, you can update one occurrence. All references to that
department are updated automatically.
Storing multiple occurrences of the same data is rarely a good thing. Good relational database
design separates application entities into their own tables. Key values from one table are often
stored in a related table rather than repeating the information. The key value is used to join the
data between the tables to return the complete set of data required.
About database basics 33