Logical Table Sources (Mappings)

You can add a new logical table source, edit or delete an existing table source, create or change mappings to the table source, and define when to use logical tables sources and how content is aggregated. Additionally, you can copy aggregation content to the Windows clipboard or from another logical table source, and check the aggregation content of logical fact table sources.

You would add new logical table sources when more than one physical table could be the source of information. For example, many tables could hold information for revenue. You might have three different business units (each with its own order system) where you get revenue information. In another example, you might periodically summarize revenue from an orders system or a financial system and use this table for high-level reporting.

One logical table source folder exists for each logical table. The folder contains one or more logical table sources. These sources define the mappings from the logical table to the physical table. Complex mappings, including formulas, are also configured in the logical table sources.

Logical tables can have many physical table sources. A single logical column might map to many physical columns from multiple physical tables, including aggregate tables that map to the column if a query asks for the appropriate level of aggregation on that column.

When you create logical tables and columns by dragging and dropping from the Physical layer, the logical table sources are generated automatically. If you create the logical tables manually, you need to also create the sources manually.

For examples of how to set up fragmentation content for aggregate navigation, refer to Specify Fragmentation Content.

This section includes the following topics:

• Creating or Removing a Logical Table Source
• Defining Physical to Logical Table Source Mappings
• Defining Content of Logical Table Sources

  Creating or Removing a Logical Table Source

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  Use the General tab of the Logical Table Source dialog box to define general properties for the logical table source.
  To create a logical table source
  1. In the Business Model and Mapping layer, right-click a logical table and choose New Object > Logical Table Source.
  2. In the Logical Table Source dialog box, click the General tab, and then type a name for the logical table source and click Add.
  3. In the Browse dialog box, you can view joins and select tables for the logical table source.
     When there are two or more tables in a logical table source, all of the participating tables must have joins defined between them.
  4. To view the joins, in the Browse dialog box, select a table and click View.
     • In the Physical Table dialog box, review the joins, and then click Cancel.
  5. To add tables to the table source, select the tables in the Name list and click Select.
  6. In the Logical Table Source dialog box, click the Column Mapping tab and complete the fields using the instructions in Defining Physical to Logical Table Source Mappings.
  7. In the Logical Table dialog box, click the Content tab and complete the fields using the instructions in Defining Content of Logical Table Sources.
  8. Click OK.
  To remove a table as a source
  1. In the Business Model and Mapping layer, right-click a logical table source and choose Properties.
  2. In the Logical Table Source dialog box, click the General tab.
  3. In the tables list, select the table you want to remove and click Remove.
  4. After removing the appropriate table, click OK.

  Example of Creating Sources for Each Level of Aggregated Fact Data

  In addition to creating the source for the aggregate fact table, you should create corresponding logical dimension table sources at the same levels of aggregation.
  NOTE:  You need to have at least one source at each level referenced in the aggregate content specification. If the sources at each level already exist, you do not need to create new ones.
  For example, you might have a monthly sales table containing a precomputed sum of the revenue for each product in each store during each month. You need to have the following three other sources, one for each of the logical dimension tables referenced in the example:
  • A source for the Product logical table with one of the following content specifications:
    • By logical level: ProductDimension.ProductLevel
    • By column: Product.Product_Name
  • A source for the Store logical table with one of the following content specifications:
    • By logical level: StoreDimension.StoreLevel
    • By column: Store.Store_Name
  • A source for the Time logical table with one of the following content specifications:
    • By logical level: TimeDimension.MonthLevel
    • By column: Time.Month