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Creating a simple overview diagram

In the last lesson, you created a physical data model and an overview diagram of the data model. You can use diagrams in the workbench to visualize and modify data models.

The default overview diagram contains all objects that are contained in the GOSALESDW schema. However, when you are working with a large data model, you can create simplified overview diagrams so that they contain only the objects that you are interested in. You can create multiple diagrams for one data model, each with different objects.

You want to add a column to the EMP_EMPLOYEE_DIM table to document the middle initial of employees. Before you add the column, you should create a simple overview diagram that will help you to visualize the changes to your data model.

In this lesson, you will create a new overview diagram that contains the following tables from the GOSALESDW schema:
  • EMP_EMPLOYEE_DIM
  • EMP_POSITION_LOOKUP
  • EMP_TERMINATION_LOOKUP
  • GO_GENDER_LOOKUP

To create a simple overview diagram:

  1. Make sure that the sample_model.dbm file is still open in the physical data model editor. To view or modify objects in a data model, the model must always be open in the editor.
  2. In the Data Project Explorer, locate the GOSALESDW schema node: EMPLOYEE > Data Models > sample_model.dmb > GSDB > GOSALESDW.
  3. Create a new overview diagram. Expand the GOSALESDW schema and right-click the Diagrams folder, then select New Overview Diagram.
    Tip: As an alternative to these steps, you can also select New Blank Diagram, and then drag and drop objects from the Data Project Explorer to the diagram surface.
  4. In the window that opens, specify the following settings:
    Diagram name
    Type myGOSALESDW.
    Infer implicit relationships
    Do not select the check box.
    Include selected elements
    Select the check box next to the following schemas:
    • EMP_EMPLOYEE_DIM
    • EMP_POSITION_LOOKUP
    • EMP_TERMINATION_LOOKUP
    • GO_GENDER_LOOKUP
    The window will look like the following image.
    Screen capture showing the tables selected as described in this step.
  5. Click OK to create the simplified overview diagram.
The new myGOSALESDW diagram opens in the diagram editor and is displayed in the Data Project Explorer in the Diagrams folder under the GOSALESDW schema.
Tip: Move the tables in the diagram closer together so that you can see them all at the same time. You can use the shaded box in the Outline view to move the focus in the diagram, then highlight diagram objects and drag them to move them.
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