1. Building Semantic Models in Oracle Analytics Cloud
  2. Create and Build Your Model
  3. Manage Logical Table Sources
  4. Modify a Logical Table Source's Logical Column to Physical Column Mappings

Modify a Logical Table Source's Logical Column to Physical Column Mappings

Semantic Modeler automatically maps logical columns to physical columns when you drag and drop a table from the physical layer to the logical layer, or when you add additional logical table sources to a logical table. You can modify these default column mappings.

You must include a physical table source to make its column available for use in column mapping. See Add Logical Table Sources.

Logical to physical column mapping can also be used to specify transformations that occur between the physical layer and the logical layer. The transformations can be simple, such as changing an integer data type to a character, or more complex, such as applying a formula to find a percentage of sales per unit of population. Applying these transformations is typically referred to as creating calculated items.

The data type of a logical column is determined by its logical table source mappings. For example, if a logical column has one physical source with a data type of VARCHAR(50) not-nullable, and another physical source with a VARCHAR(20) data type, nullable, then the data type of the logical column is VARCHAR(50) nullable. This final type is called a promoted type. Because of the rules governing logical table source mappings, you can't map physical sources with data types that are promotable such as an INT with a VARCHAR.

  1. On the Home page, click Navigator and then click Semantic Models.
  2. In the Semantic Models page, click a semantic model to open it.
  3. Click Logical Layer.
  4. In the Logical Layer pane, browse for and double-click the table with the column mappings you want to modify.
  5. In the logical table, click the Sources tab.
  6. In the logical table sources list table, click a logical table source to select it and then click Detail view to open the properties pane.
  7. Scroll to Column Mapping, locate and double-click the column mapping that you want to change.
  8. Click the physical column field's dropdown button and browse for and select the name of the physical column to map the corresponding logical column to.
  9. Click Save.