Defining and Creating a Linked Universe

A linked universe is a .unx universe that contains a link to a designated core universe in the Business Objects (BI) Platform Repository. It inherits the core universe's data foundation and business layer as read-only resources. You can create views and objects from components of the core universe, as well as add new tables and objects that are independent of the core universe. When changes are made in the core universe, they are automatically propagated to the shared components in its linked universes.

A linked universe can reference one or more core universes, so it can use components in the core data foundation and business layer of each universe.

The linking process makes it appear as though the data foundation and business layer of universe A are part of universe B. However, they are just a look-up (signified by graying them out in universe B) to universe A and cannot be edited in universe B.

You have the following advantages when linking universes:

• Reduce development and maintenance time: When you modify a component in the core universe, the changes are made to the same component in all of its linked universes when each universe is refreshed.

• Centralization of components: Frequently used components can be centralized in a core universe and then included in all linked universes. You do not have to recreate components each time you create a new universe.

• Facilitate specialization of universe design: Universe development can be split between developers who create core universes, and specialized designers who create more functional business layers based on their specific field.

You create a linked universe in one of the two following ways:

1. By creating a new linked universe directly from a core universe in the SAP Business Intelligence Platform. The core business layer and data foundation become the foundation for the new universe.

2. By adding a link to a core universe from an existing universe. The core business layer and data foundation are added to the current business layer and data foundation.

For a universe to be used as a core universe, the following requirements and restrictions apply:

• The core universe must be a .unx file version 4.2 format.

• The core universe must have a single-source data foundation.

• The core universe cannot already be a linked universe.

• The core universe cannot be an OLAP universe.

1. Open a business layer that you want to link to a core universe.

2. If the data foundation is open, save and close it. The linked universe data foundation is updated with the core universe components when it is reopened after the universes have been linked.

   Note

   If you leave the data foundation open, you will not see the added core components until you close and reopen the linked universe data foundation.

3. In the Business Layer Editor, click the Core Business Layers tab.

4. Click the + Add Core button. A list of repository folders and files appears.

5. In the left pane, browse to and select a universe folder, then click a universe name in the right pane. This universe is the core universe that you want to link to your active universe.

6. Click OK. The name of the core universe appears in the list of core universes in the Core Business Layers tab. The business layer components from the core universe appear in the business layer browsing pane to the left of the Business Layer Editor.

7. Open the data foundation for the newly linked universe from the Local Project browser.

   Note

   When you link to a core universe, a unique identifier is attributed to each core universe component. Any objects associated with core components in the linked business layer or data foundation, for example joins, views, or dimensions, are based on these identifiers. If you remove the core universe and then re-link it, a new set of identifiers will be attributed to the same objects. You must re-associate all of the previous components with the core universe.

Not all core universe components are inherited by a linked universe. These components include:

• Rights: You must ensure that the linked universe rights are compatible with the core universe rights.
• Connection: When creating a new linked universe or adding a core universe, you have a choice to reuse the core universe connection or use another compatible connection that allows you to access components outside of the core universe. It is recommended that you use another connection.
• Aliases and Contexts: You must create new aliases and contexts.
• Views: You must create new data foundation and business layer views.
• Security: You must create new security rights for the linked universe.
• Custom Navigation Paths: You must create new navigation paths.