Identifying Fact and Dimension Tables

When designing a data warehouse, you will need to identify which of your tables and views represent facts (containing numerical values such as sales, revenue, or budget figures), and which dimensions (providing ways of aggregating these figures, such as by region, date, customer, or product). PowerDesigner can retrieve the multidimensional type of a table by analyzing the references attached to it, where child tables or views are identified as candidate facts and parent tables or views are identified as candidate dimensions.

1. Select  Tools  Multidimension  RetrieveMultidimensional Objects  to open the Multidimensional Objects Retrieval Wizard.
2. Specify the objects to be retrieved. By default both Facts and Dimensions will be retrieved.
   Note

   If you are working with SAP® IQ v12.0 or higher, you can also select to automatically rebuild join indexes after retrieving multidimensional objects. For more information, see Join Indexes (IQ/Oracle).

3. [optional] Click the Selection tab to specify which tables to consider as candidates for fact or dimension tables. By default, all tables except those that have their Dimensional type set to Exclude are selected (see Table Properties).
4. Click OK to retrieve the multidimensional objects.

   The selected tables are assigned a multidimensional type, and a type icon is displayed in the upper left corner of each table's symbol:

   Fact table	Dimension table

5. [optional] Review the types identified by PowerDesigner and, if necessary, modify them by changing the value of the Dimensional type field on the General tab of the table or view property sheet.