In the Logical Dimension dialog, in the General tab, type a name for the If the dimension is a time dimension, select Time. If the dimension is an unbalanced dimension, select Ragged. If the dimension is a skip-level dimension, select Skipped Levels. Opti

Working with Logical Dimensions 9-5 ■ Creating Logical Levels in a Dimension ■ Associating a Logical Column and Its Table with a Dimension Level ■ Identifying the Primary Key for a Dimension Level ■ Selecting and Sorting Chronological Keys in a Time Dimension ■ Adding a Dimension Level to the Preferred Drill Path Creating Dimensions in Level-Based Hierarchies After creating a dimension, each dimension can be associated with attributes columns from one or more logical dimension tables and level-based measures from logical fact tables. After you associate logical columns with a dimension level, the tables in which these columns exist appear in the Tables tab of the Dimension dialog. To create a dimension with a level-based hierarchy: 1. In the Business Model and Mapping layer of the Administration Tool, right-click a business model and select New Object Logical Dimension Dimension with Level-Based Hierarchy . Note that this option is only available when there is at least one dimension table that has no dimension associated with it.

2. In the Logical Dimension dialog, in the General tab, type a name for the

dimension. The Default root level field is automatically populated after you associate logical columns with a dimension level.

3. If the dimension is a time dimension, select Time.

4. If the dimension is an unbalanced dimension, select Ragged.

5. If the dimension is a skip-level dimension, select Skipped Levels.

6. Optional Type a description of the dimension.

7. Click OK.

Creating Logical Levels in a Dimension When creating logical levels in a dimension, you also create the hierarchy by identifying the type of level and defining child levels. See Automatically Creating Business Model Objects for Multidimensional Data Sources for more information about creating hierarchies for a multidimensional data source. To define general properties for a logical level in a dimension: 1. In the Business Model and Mapping layer of the Administration Tool, right-click a dimension and select New Object, then select Logical Level. 2. In the Logical Level dialog, in the General tab, specify a name for the logical level. Note: It is a best practice to ensure that the physical hierarchy type set in the Physical layer matches the dimension properties you select in the Business Model and Mapping layer. See Working with Physical Hierarchy Objects for more information. In addition, you must ensure that the Ragged and Skipped Levels dimension properties are set correctly for queries to work. 9-6 Metadata Repository Builders Guide for Oracle Business Intelligence Enterprise Edition

3. For Number of elements at this level, specify the number of elements that exist at

this logical level. If this level will be the Grand Total level, leave this field blank. The system will set to a value of 1 by default. The number does not have to be exact, but ratios of numbers from one logical level to another should be accurate. For relational sources, you can retrieve the row count for the level key and use that number as the number of elements. For multidimensional sources, you can use the number of members at that level. The Oracle BI Server uses this number when selecting which aggregate source to use. For example, when aggregate navigation is used, multiple fact sources exist at different grains. The Oracle BI Server multiplies the number of elements at each level for each qualified source as a way to estimate the total number of rows for that source. Then, the Oracle BI Server compares the result for each source and selects the source with the lowest number of total elements to answer the query. The source with the lowest number of total elements is assumed to be the fastest. 4. Choose one of the following options, if appropriate: – If the logical level is the Grand Total level, select Grand total level. There should be only one Grand Total level for a dimension. – If measure values at a particular level fully constitute aggregated measures at its parent level, select Supports rollup to higher level of aggregation. 5. To define child logical levels, click Add. 6. In the Browse dialog, select the child logical levels and click OK. The child levels appear in the Child Levels pane. 7. To remove a previously defined child level, select the level in the Child Levels pane and click Remove. The child level and all of its child levels are deleted from the Child Levels pane. 8. Optional Type a description of the logical level.

9. Click OK.