Building the Data Warehouse

Скачать в pdf «Building the Data Warehouse»


creative indexes/profiles

existing systems


Figure 3.32 Examples of creative indexes:


•    The top 10 customers in volume are_.


•    The average transaction value for this extract was $nnn.nn.


•    The largest transaction was $nnn.nn.


•    The number of customers who showed activity without purchasing was nn.


The creative index does a profile on items of interest to the end user, such as the largest purchases, the most inactive accounts, the latest shipments, and so on. If the requirements that might be of interest to management can be anticipated (admittedly, they cannot in every case), at the time of passing data to the data warehouse, it makes sense to build a creative index.


A final technique that the data warehouse designer should keep in mind is the management of referential integrity. Figure 3.33 shows that referential integrity appears as “artifacts” of relationships in the data warehouse environment.


In the operational environment, referential integrity appears as a dynamic link among tables of data. But because of the volume of data in a data warehouse, because the data warehouse is not updated, and because the warehouse represents data over time and relationships do not remain static, a different approach should be taken toward referential integrity. In other words, relationships of data are represented by an artifact in the data warehouse environment. Therefore, some data will be duplicated, and some data will be deleted when


data warehouse and referential integrity


CL L3


СГ L3


□ □□ □ □ ппп □ □ П°ПППп

Скачать в pdf «Building the Data Warehouse»