Chapter 15 DBMS-Specific Features

Rebuild bitmap join indexes for all references linked to a fact table

You can automatically generate a bitmap join index for each fact table and the dimension tables that it references. Each automatically generated bitmap join index consists of the references that link a fact table to all the dimension tables located on a single axis proceeding from the fact table.

A reference between two fact tables does not generate any bitmap join index. A bitmap join index is constrained and can only be defined for tables that are organized in a connected tree.

Parameter Result of selection
Delete and Rebuild When selected, all existing indexes are deleted before join index rebuild.
Preserve When selected, preserves all existing join indexes in the PDM.

Steps To rebuild bitmap join indexes for all references linked to a fact table:

  1. Select Tools→Rebuild Objects→Rebuild Join Indexes.

    The Rebuild Join Indexes dialog box is displayed.
  2. Click the Selection tab.

    The Selection tab is displayed.
  3. Select one or more fact tables from the list.
  4. Click OK.

    A confirmation box asks if you want to continue.
  5. Click Yes.

    A bitmap join index is automatically generated for each fact table.

    Note   Displaying automatically generated bitmap join indexes
    Automatically generated bitmap join indexes appear in the list of join indexes. To display the list, select Model→Join Indexes.


 

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