1. CSCI 4333 Database Design and Implementation – Exercise (5)
Xiang Lian
The University of Texas Rio Grande Valley
Edinburg, TX 78539

2. I/O Cost of Accessing Files
Assume that a data file has 500 pages
Each page can store 50 index entries or 10 tuples
A range query returns 20 tuples
What is the I/O cost of accessing files/index? (assuming log2500 = 9)
Heap file
I/O cost for index entries:
I/O cost for tuples:
Sorted file
Unclustered index
Clustered index

3. Sparse Index vs Dense Index
Which is sparse index? Which is dense index?

4. B+-Tree Index Insert tuples with key 23* Root 19 24 33 2* 3* 5* 7* 14*
16*
19*
20*
22*
24*
27*
29*
33*
34*
38*
39* 14

5. B+-Tree Index (cont'd) Insert tuples with key 8* Root 19 24 33 2* 3*5* 7*
14*
16*
19*
20*
22*
24*
27*
29*
33*
34*
38*
39* 14
23*

6. B+-Tree Index (cont'd)
Insert tuples with key 8* (Please complete empty index entries)
Root 19 24 33 2* 3* 5* 7*
14*
16*
19*
20*
22*
24*
27*
29*
33*
34*
38*
39* 14
23*
Root 24 33
19*
20*
22*
24*
27*
29*
33*
34*
38*
39*

7. B+-Tree Index (cont'd) Insert tuples with key 8* Root Root 19 24 33 2*3* 5* 7*
14*
16*
19*
20*
22*
24*
27*
29*
33*
34*
38*
39* 14
23* 2* 3*
Root 19 24 33
14*
16*
19*
20*
22*
24*
27*
29*
33*
34*
38*
39* 14 5 7* 5* 8*

8. Extendible Hash Index (1)2 01 00 11 10 16 20 1
Directory
Buckets 3 7 A B C D
Insert 2
h(2) = 00010 18

9. Extendible Hash Index (2)01 00 11 10 16 20 1
Directory
Buckets 3 7 A B C D
Insert 19
h(1) = 00001
h(2) = 00010
h(3) = 00011
h(7) = 00111
h(16) = 10000
h(18) = 10010
h(19) = 10011
h(20) = 10100 18

10. Extendible Hash Index (3)2 16 20 A B C D
Insert 19 3
000
h(1) = 00001
h(2) = 00010
h(3) = 00011
h(7) = 00111
h(16) = 10000
h(18) = 10010
h(19) = 10011
h(20) = 10100 2
001 1
010
011 2 2
100 18
101 3
110
111 3
Directory
Buckets