1. Tree-based Indexing
Hessam Zakerzadeh

2. ISAM (Indexed Sequential Access Method)
ISAM was originally developed by IBM for mainframe computers
Allows records to be accessed:
sequentially (in the order they were entered)
randomly (with an index)

3. ISAM (Indexed Sequential Access Method)
Static index structure.
Data values reside in leaf nodes.
Effective when file is not frequently updated.

4. Leaf pages contain data entries.
Non-leaf
Pages
Leaf
Pages
Overflow
page
Primary pages
Leaf pages contain data entries.

5. After Inserting 23*, 48*, 41*, 42* ... Root Index Pages Primary Leaf40
Pages 20 33 51 63
Primary
Leaf
10*
15*
20*
27*
33*
37*
40*
46*
51*
55*
63*
97*
Pages
23*
48*
41*
Overflow
Pages
42*

6. Give an example of when you would use each element (A or B) for each of the following ‘A versus B’ pairs:
A hashed index using Alternative (1) versus heap file organization.

7. Give an example of when you would use each element (A or B) for each of the following ‘A versus B’ pairs:
A hashed index using Alternative (1) versus heap file organization.
hashed index : when most of the queries are equality queries.
heap file : when a file is scanned in sequential order.

8. Extendible Hashing versus Linear Hashing.

9. Extendible Hashing versus Linear Hashing.
Extendible Hashing : When data values lead to a skewed distribution
Linear Hashing : A large data file requiring a directory to span several pages.

10. Static Hashing versus Linear Hashing.

11. Static Hashing versus Linear Hashing.
Static Hashing :When the number of records are constant
Linear Hashing: When number of records varies, and hash key values are uniformly distributed.

12. Static Hashing versus ISAM

13. Static Hashing versus ISAM
Static Hashing: When the number records are constant and most of the queries are equality search
ISAM :When queries involve range queries

14. Linear Hashing versus B+ trees

15. Linear Hashing versus B+ trees
Linear Hashing :When queries are equality search
B+ trees :When queries are range search