5 Data Warehouse projects
as both a fact and a dimension - for example, Customers. In such cases, a report could be
generated that relates to the state of the fact, such as the time a claim was submitted to the
time it was approved.
6. Click Next.
7. In the Facts screen, choose one fact for the star schema and then click Next. The Dimensions screen is
displayed. The left pane lists the dimensions that can be selected while the right pane displays a
diagram of the star schema with the selected dimensions. You can view a dimension’s lineage by
selecting the desired dimension and then clicking the Lineage button. For more information on
lineage, see Lineage and impact analysis (page 177).
The left pane of the Dimensions screen contains the following areas:
l
Existing Dimensions - Lists the dimensions that already exist in your data mart. Note that only
dimensions that are relevant to the selected fact table will be displayed.
l
Create New Dimensions - Lists all of the dimensions that can be added to the star schema.
l
Date Dimensions - Lists all of the Date dimensions that can be added to the star schema. Note
that these dimensions will only be available for selection if you added the Date and Time
entities to your model. For an explanation of how to do this, see Adding Date and Time entities
to your model (page 178).
l
Time Dimensions - Lists all of the Time dimensions that can be added to the star schema. Note
that these dimensions will only be available for selection if you added the Date and Time
entities to your model. For an explanation of how to do this, see Adding Date and Time entities
to your model (page 178).
When adding dimensions using the wizard, if a root dimension already exists in the data
mart, any dimensions selected under the root dimension will be ignored.
Workaround: Edit the dimension and delete or add columns as required.
8. Choose which dimensions to include in the star schema and then click Next.
9. If you chose Star Schema with State Orientation as your star schema type, click Finish. Otherwise,
continue from Step Adding data marts and star schemas (page 225) below.
10. In the Transaction Date screen, choose which Transaction Date to include in the data mart fact table.
Selecting a Transaction Date enables you to retrieve the required data, even if the Dimension table
contains multiple versions of the same record.
For example, a car salesman wants to know how many customers bought cars in New York between
2013 and 2015. Selecting OrderDate as the Transaction Date for the Customers Dimension would make
it possible to retrieve this information, even if a customer moved to a different city (which would also
result in a new record being added to the data mart).
11. If you chose Transactional as your star schema fact type, click Finish. If you chose Aggregated as your
star schema fact type, continue from Step Adding data marts and star schemas (page 225) below.
12. In the Aggregated Fact screen:
a. Select one or more columns from the Fact table on the left of the screen.
You can select multiple columns by holding down the [Shift] (sequential selection) or
[Ctrl] (non-sequential selection) buttons while selecting the columns.
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