Consider the following example:
|Traveling Salesman||Brand||Product Type|
|Jack Schneider||Acme||Vacuum Cleaner|
|Willy Loman||Robusto||Pruning Shears|
|Willy Loman||Robusto||Vacuum Cleaner|
|Willy Loman||Robusto||Umbrella Stand|
|Louis Ferguson||Robusto||Vacuum Cleaner|
|Louis Ferguson||Acme||Vacuum Cleaner|
|Louis Ferguson||Acme||Lava Lamp|
|Louis Ferguson||Nimbus||Tie Rack|
In the absence of any rules restricting the valid possible combinations of Traveling Salesman, Brand, and Product Type, the three-attribute table above is necessary in order to model the situation correctly.
Suppose, however, that the following rule applies: A Traveling Salesman has certain Brands and certain Product Types in his repertoire. If Brand B is in his repertoire, and Product Type P is in his repertoire, then (assuming Brand B makes Product Type P), the Traveling Salesman must offer only the products of Product Type P made by Brand B.
In that case, it is possible to split the table into three:
|Traveling Salesman||Product Type|
|Jack Schneider||Vacuum Cleaner|
|Willy Loman||Pruning Shears|
|Willy Loman||Vacuum Cleaner|
|Willy Loman||Umbrella Stand|
|Louis Ferguson||Vacuum Cleaner|
|Louis Ferguson||Lava Lamp|
|Louis Ferguson||Tie Rack|
Note how this setup helps to remove redundancy. Suppose that Jack Schneider starts selling Robusto's products. In the previous setup we would have to add two new entries since Jack Schneider is able to sell two Product Types covered by Robusto: Breadboxes and Vacuum Cleaners. With the new setup we need only add a single entry (in Brands By Traveling Salesman).
Read more about this topic: Fifth Normal Form
Other articles related to "example":
Example may also refer to:
- Example (musician), a British musician
- Example, Florida rock band For Squirrels' sole major-label album, released in 1995
- example.com, example.net, example.org, example.edu and .example, domain names reserved for use in documentation as examples
- HMS Example (P165), an Archer-class patrol and training vessel of the British Royal Navy
- The Example, a 1634 play by James Shirley
- The Example (comics), a 2009 graphic novel by Tom Taylor and Colin Wilson
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... Then the projection on the first component of a distribution's wave front set is nothing else than its classical singular support, i.e ... the complement of the set on which its restriction would be a smooth function ...
Famous quotes containing the word example:
“Our intellect is not the most subtle, the most powerful, the most appropriate, instrument for revealing the truth. It is life that, little by little, example by example, permits us to see that what is most important to our heart, or to our mind, is learned not by reasoning but through other agencies. Then it is that the intellect, observing their superiority, abdicates its control to them upon reasoned grounds and agrees to become their collaborator and lackey.”
—Marcel Proust (18711922)