Vertical Decomposition
Suppose we want to speed up Q6. We can make it read fewer pages by decomposing:
- Rink_phone (name, phone), clust. index on name
- Rink_cap (name, capacity), clust. index on capacity
Create a view to preserve external schema
IC (FD) maintenance choices:
- leave it to user (scary!)
- allow inserts to “rink” view, not to base relations
- application pgm. to force user to enter both (atomic)
- insert into one base relation triggers insert into other