Select Physical Diagram and then one of the joins options. From the shortcut menu, select New Object, then select Logical Column. In the General tab, type a name for the logical column. Select Writeable to enable write back for this column. See

Working with Logical Tables, Joins, and Columns 8-11 This is a performance tuning parameter. In general, the larger its value, the fewer parameterized queries need to be generated. Values that are too large can result in parameterized queries that fail due to back-end database limitations. Setting the value to 0 zero turns off drive table joins. ■ MAX_QUERIES_PER_DRIVE_JOIN This is used to prevent runaway drive table joins. If the number of parameterized queries exceeds its value, the query is terminated and an error message is returned to the user. Identifying Physical Tables That Map to Logical Objects The Physical Diagram shows the physical tables that map to the selected logical object and the physical joins between each table. One of the joins options, Objects and Direct Joins within Business Model, is unique to the logical layer. It creates a physical diagram of the tables that meet both of the following conditions: ■ Tables in the selected objects and tables that join directly ■ Tables that are mapped exist in logical table sources in the business model in the business model To open the Physical Diagram for a logical object: 1. In the Business Model and Mapping layer of the Administration Tool, right-click a business model, logical table, or logical table source.

2. Select Physical Diagram and then one of the joins options.

3. Click and drag any object to more clearly view the relationship lines, such as one-to-many. Creating and Managing Logical Columns Many logical columns are automatically created by dragging tables from the Physical layer to the Business Model and Mapping layer. Other logical columns, especially ones that involve calculations based on other logical columns, can be created later. Logical columns are displayed in a tree structure expanded out from the logical table to which they belong. If the column is a primary key column or participates in a primary key, the column is displayed with a key icon. If the column has an aggregation rule, it is displayed with a ruler icon. You can also reorder logical columns in the Business Model and Mapping layer. This section contains the following topics: ■ Creating Logical Columns ■ Basing the Sort for a Logical Column on a Different Column ■ Enabling Double Column Support by Assigning a Descriptor ID Column ■ Creating Derived Columns ■ Setting Default Levels of Aggregation for Measure Columns ■ Associating an Attribute with a Logical Level in Dimension Tables ■ Moving or Copying Logical Columns 8-12 Metadata Repository Builders Guide for Oracle Business Intelligence Enterprise Edition Creating Logical Columns The following procedure explains how to create logical columns in the Business Model and Mapping layer. To create a logical column: 1. In the Business Model and Mapping layer, right-click a logical table.

2. From the shortcut menu, select New Object, then select Logical Column.

3. In the General tab, type a name for the logical column.

The name of the business model and the associated logical table appear in the Belongs to Table field.

4. Select Writeable to enable write back for this column. See

Enabling Write Back On Columns for more information.

5. Optionally, you can assign a different column on which to base the sort order for a