1. Recursive Relationship
Customer 1
comprises
A customer comprises zero or more customers
© Ron McFadyen

2. Hierarchies
Customer1 is hierarchically structured. Any of these customers are ones you may deal with. Each of these appears in the customer dimension.
Customer 1
Customer 2
Customer 7
Customer 3
Customer 4
Customer 8
Customer 5
Customer 6
© Ron McFadyen

3. Hierarchies The valid paths are: Customer 1 Customer 2 Customer 7
© Ron McFadyen

4. Consider the helper/bridge table
Customer bridge
Parent customer key
Subsidiary customer key
Levels from parent
Level name
Bottom flag
Top flag
Some useful additional attributes
Levels from parent
Level name
Bottom flag
Top flag
And we’ll add one extra row for each node paired with itself
© Ron McFadyen

5. Subsidiary customer key Levels from parent Level name Bottom flag
Bridge table
Customer bridge
Parent customer key
Subsidiary customer key
Levels from parent
Level name
Bottom flag
Top flag
And we’ll add one extra row for each node paired with itself
How many rows will there be?
© Ron McFadyen