HASHING IN DBMS

What is the main focus of module 29 in database management systems?

• Indexing and hashing

• Query optimization

• Network security

• Data visualization

What is the most powerful data structure introduced in the last module?

• Binary search tree

• B-tree

• B+ tree

• Hash table

What is the basic logical concept of a bucket in hash file organization?

• A unit of storage containing one or more records

• A search key value

• A single record

• A disk block

What is the purpose of a hash function in hash file organization?

• To encrypt data

• To compress data

• To sort records alphabetically

• To locate records directly from their search key value

What is the worst possible hash function according to the text?

• One which maps each key to a unique bucket

• One which maps all key values to the same bucket

• One which generates random bucket addresses

• One which distributes keys evenly across all buckets

What is the main advantage of dynamic hashing over static hashing?

• Eliminates the need for hash functions

• Provides faster access time

• Requires less memory

• Allows the number of buckets to change dynamically

What is the primary disadvantage of static hashing?

• Has a higher memory overhead

• Does not allow bucket overflow

• Does not support primary hash indexing

• Requires periodic reorganization

Which database system supports hash index but does not recommend it?

• PostgreSQL

• MySQL

• Oracle

• SQL Server

What is the main advantage of bitmap indices?

• Efficient for querying on multiple keys

• Optimize worst-case access time

• Require less storage space

• Support primary hash indexing

What operation can be easily computed using bitmap indices?

• Intersection and union

• Subtraction and division

• Exponentiation and logarithm

• Multiplication and addition