The Data Model Resource Book, Volume 3: Universal Patterns for Data Modeling

Silverston c05.tex V2 - 11/21/2008 3:04am Page 213

Level 3 Classification Pattern 213

To further illustrate this pattern, we continue with the scenario that we

described in the previous section. The CIO of Euro-Electronics has stated

that one of the biggest IT issues the company has is that sales and marketing

people keep changing the way they want to slice and dice product information.

For example, they continually come up with new ways to analyze product

information, such as various product groupings, subgroupings, usage, types of

materials, and so on. Each new type of category that they add, change, or make

obsolete may need new (or changed) entities and eventually new (or changed)

tables. This has become a headache for the overstretched programmers in

the IT department. Sales and marketing have threatened to employ their

own in-house programmers to get their reports up and running. The CIO

wants to have a flexible architecture in place to alleviate the pressure on his

programmers so that he can meet the needs of sales and marketing. Based

on this need and using the Level 3 Pattern, the data professional produced

Figure 5-9.

PRODUCT CATEGORY CLASSIFICATION

PRODUCT CATEGORY CLASSIFICATION ID ID (PK)

* PRODUCT ID ID (FK)(UID)

* PRODUCT CATEGORY ID ID (FK)(UID)

* FROM DATE DATE (UID)

THRU DATE DATE

PRODUCT CATEGORY

PRODUCT CATEGORY ID ID (PK)

PARENT PRODUCT CATEGORY ID

ID (FK)(UID) ...