Join Example (cont)
Some database statistics:
| Sym |
Meaning |
Value |
| rS |
# student records |
20,000 |
| rE |
# enrollment records |
80,000 |
| cS |
Student records/page |
20 |
| cE |
Enrolled records/page |
40 |
| bS |
# data pages in Student |
1,000 |
| bE |
# data pages in Enrolled |
2,000 |
Also, in cost analyses below, N = number of memory buffers.
|