Database Reference
In-Depth Information
Notice that the Abbreviation from the States table has been changed to StateAbbreviation in the new
examples. This is one example of how this change adds clarification and allows for a more workable and detailed
table. Another change is that the StateId from the States table is no longer needed in the star design, as the need
for that particular key is removed.
When you compare the original OLTP tables (Figure
4-8
) to the OLAP tables in Figure
4-9
, notice that they
are similar but not exactly the same. The names are changed to reflect their usage, and some of the tables are
combined into a single table. The FactSales table has a composite primary key on all the dimension key columns
(with one exception, AuthorId). The FactTitleAuthors contains only two primary keys, AuthorId, and TitleId,
forming a bridge table just as in the OLTP design.
Figure 4-8.
The OLTP design
