Here, we can see how the database is navigated to determine which parts use a specific component. For example, if you start at the Hamburger bubble and navigate through the Is_a_part relationships, you see that one hamburger participates in the Value_Meal and also in the Big_Meal.

Recursive relationships can now be generated from the structure. For example, when listing the components of a Big_Meal, all components appear as shown in Table 4.2.

Table 4.2  BOM Explosion for Big_Meal.

Part 1                    Part 2                    Part 3                    Quantity
Hamburger                                                            1
                          Meat Patty                                 2
                                                    Oatmeal           4 oz.
                                                    Beef                3 oz.
                          Bun                                           1
Fries                                                                    1 order
                          Potato                                       1
                          Grease                                       1 cup
Soda                                                                    1
                          Ice                                            1/2 cup
                          Drink                                          1/3 cup

Conversely, the recursive association can be applied to any item to see its participation in other items. For example, the uses of grease can be seen by running an implosive query, as shown in Table 4.3.

Table 4.3  BOM implosion for grease.

Part1                    Part2                    Part3
Fries
                                                    Big Meal
                                                    Value Meal
Meat Patty
                          Hamburger
                                                    Big Meal
                                                    Value Meal
                          Cheeseburger
                          Big Beefy
Fried Pies
                        Value Meal

This is an excerpt from "High Performance Data Warehousing", copyright 1997.

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