Databases Reference
In-Depth Information
• he Factory Worker entity Fred has the Instance Key 942 because
the dimension row for Fred in the Factory Worker table with the
Instance Key value 942 has the Row_First_Date and Row_Last_Date
values of April 14, 2007, and Dec. 31, 9999, which inclusively sur-
round the Fact row date of Jan. 20, 2011.
• he Raw Material entity Iron Ore has the Instance Key 482 because
the dimension row for Iron Ore in the Raw Material table with the
Instance Key value 482 has the Row_First_Date and Row_Last_Date
values of May 12, 2010, and Dec. 31, 9999, which inclusively sur-
round the Fact row date of Jan. 20, 2011.
• he Location entity Atlanta Iron 35 has the Instance Key 234 because
the dimension row for Atlanta Iron 35 in the Location table with the
Instance Key value 234 has the Row_First_Date and Row_Last_Date
values of Feb. 6, 1998, and Dec. 31, 9999, which inclusively surround
the Fact row date of Jan. 20, 2011.
• he Formula entity RWU987 has the Instance Key 294 because the
dimension row for RWU987 in the Formula table with the Instance
Key value 294 has the Row_First_Date and Row_Last_Date values of
Nov. 25, 2008, and Dec. 31, 9999, which inclusively surround the Fact
row date of Jan. 20, 2011.
From the Fact rows in Table 13.12 to the Fact rows in Table 13.13, the
Instance Key for Raw Material changed from 385 to 482, and the Instance
Key for Formula changed from 294 to 762. They would not, however, exist
in two separate Fact tables. Instead, they would exist side by side in a sin-
gle Fact table, which is shown in Table 13.14.
Type 1 Time Variance
Type 1 Time Variance views all the history of the enterprise as it is now.
Chapter 12 provided a solution for organizing the Type 1 dimension tables
and views so that they join well with a Fact table that supports both Type
1 and Type 2 time variant dimensions.
• A Type 1 query of all the Manufacture_Metals_Detail rows that
include the Factory Worker entity named “Fred” will return all the
rows in Table 13.14.
