| Possible values |  |
- | Call Group1 You can relate as many subordinate call groups (of category Call Group2 )as you want to a call group of this category. Call Group2 You can subordinately relate a call group of this category to one call group of category Call Group1. Call Group2 A company that manufactures electrical goods uses the following structure to categorize the calls the company receives:
        +-------------------+-------------------+
        |Call Group1      |Call Group2     |
        +-------------------+-------------------+
        | Household items   |                 		|
        |                   | Toasters          |
        |                   | Curling tongs     |
        |                   | Hair dryers       |
      		+-------------------+-------------------+
        | Gardening items   |                   |
        |                   | Hedge trimmers    |
        |                   | Lawn mowers       |
        +-------------------+-------------------+
        | Carpentry items   |                   |
        |                   | Jigsaws           |
        |                   | Belt sanders      |
        |                   | Circular saws     |
      		+-------------------+-------------------+