Combining Data

Objectives

After completing this lesson, you will be able to:

  • Combine cubes in data mode

Combine cubes

Through merged objects, you can already synchronize data coming from different data sources. But this must be done for each object involved in this synchronization and there are some constraints. The Data mode proposes an easier way to synchronize datasets thanks to the Combine Cubes feature.

Note

For the moment, this feature is not visible by default. It must be explicitly enabled (see SAP Note 3270462) until a future patch that will correct some known issues and will enable it by default.

You may need to synchronize cubes/datasets in these two cases:

  • Left Join: to extend a dataset with columns from another dataset. For example, a dataset containing only sales facts might be extended with details of the buyers.
  • Append: to append the rows of a dataset after the rows of another one. For example, if a query retrieves a dataset for a given week whereas another query retrieves a dataset for another week. Appending these two datasets generates a single dataset for the two weeks.

The Data mode allows you to perform these two use cases through the Combine Cubes features. In the two cases, you need to define a primary and a secondary cube and a set of objects to map between the two cubes.

To combine cubes:

  • Select two nodes in the graph and click Combine in the toolbar.
  • In the Create Cube dialog box, add a Name and if needed, a Description for the new cube.
  • Select the operator to apply: Left Join or Append.
  • Click the Add Keys button to open a dialog box where you can select the objects used as keys for the operation. By default, objects with the same name are used as keys.

Deprecated cubes and objects

A cube used as parent (primary or secondary cube) of a combined cube will be deprecated:

  • This cube and its objects are replaced by the combined cube and its objects.
  • It is not possible to use it as parent of another combined cube.
  • In the Graph Panel, the name of this cube is crossed out.
  • When you return to Design mode, this cube is no longer available and is replaced by the combined cube. In Data mode, you can see which cubes are available in Design mode by selecting the Main View option instead of the All Cubes in the Main Side PanelObjects tab.

Once the combined cube has been created, the objects of the parent cubes return values resulting from the operation (Left Join or Append) that defines the combined cube. If these objects were already used in document report elements, this may impact the values they return.

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