View and Edit Relationships
The Design tab in the PowerPivot window contains tools to help you view and manage table relationships that have been defined in your workbook. For information about how relationships are used in PowerPivot for Excel, see Relationships Overview.
In Windows Vista and Windows 7, features in the PowerPivot window are available on a ribbon, which is discussed in this topic. In Windows XP, features are available from a set of menus. If you are using Windows XP and want to see how the menu commands relate to the ribbon commands, see The PowerPivot UI in Windows XP.
To view and edit existing relationships
When editing a relationship, consider the following:
There can be only one relationship between each pair of tables.
The data values in Related Lookup Column must be unique. In other words, the column cannot contain duplicates.
Each table must have a single column that uniquely identifies each row in that table.
The data types in Column and Related Lookup Column must be compatible. For more information about data types, see Data Types Supported in PowerPivot Workbooks.
For a complete list of requirements, see "Requirements for Relationships" in Relationships Overview.