Create or Modify a Physical Column

You can create a new column in a physical table, or update an existing or imported column's properties. Physical columns store data within tables in the physical database.

Remember that if you create, modify, or delete the physical table's columns, then any alias tables that use the physical table as its source reflect those changes.

When you create or update a physical table, you can set its Source property to use a stored procedure or select statement to populate columns. See Populate Physical Columns with a Stored Procedure or Select Statement.

Use this information to help you set a column's properties:

• Type - Indicates the column's data type. Use caution when changing the data type. Setting the values to data types that are incorrect in the underlying data source might cause unexpected results. If there are any data type mismatches, correct them in the semantic model or reimport the columns that have mismatched data types.

  If you reimport columns, you also need to remap any logical column sources that reference the remapped columns. The data type of a logical column in the business model must match the data type of its physical column source. The Oracle Analytics query engine passes these logical column data types to client applications.

  Longvarchar and longvarbinary data types are supported for writing complete Logical SQL statements into usage tracking tables for debugging purposes. They aren't supported for general-purpose queries, and can't be displayed in Oracle BI Server.

• Nullable - Specifies whether null values are allowed for the column. If null values can exist in the underlying table, you need to select this option. This allows null values to be returned to the user, which is expected with certain functions and with outer joins. It's generally safe to change a non-nullable value to a nullable value in a physical column.

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 Physical Layer.
4. In the database pane, browse for and double-click the table where you want to add or modify a column.
5. In the physical table, click the Columns tab.
6. Click Add Column and select Create New Column to create a new column in the physical table. Or in the table, click a column to highlight it, and then click it again to enable the fields to be updated.
7. Optional: To duplicate a column, hover over the column you want to duplicate and click its Row Menu and click Duplicate.
8. Specify the column's properties and then click off of the column.
9. Click Save.