DBMS_7th_ch14

What is the purpose of indexing mechanisms?

• To slow down access to desired data

• To speed up access to desired data

• To confuse users while searching for data

• To increase the size of the original file

What is a search key in the context of indexing?

• An attribute used to look up records in a file

• A key used to encrypt the data

• A key used to lock the database

• A key used to open the index file

What is the main difference between ordered indices and hash indices?

• Ordered indices are slower than hash indices, but occupy less space

• Ordered indices store search keys in sorted order, while hash indices distribute search keys uniformly across buckets

• Ordered indices use a hash function, while hash indices use sorting

• Hash indices are used for text data, while ordered indices are used for numerical data

What is the purpose of a primary index in ordered indices?

• To store non-sequential keys

• To specify the sequential order of the file

• To store secondary keys

• To store duplicate keys

What is the advantage of B+-tree index files over indexed-sequential files?

• B+-trees have a higher deletion time compared to indexed-sequential files

• B+-trees automatically reorganize with small changes, avoiding periodic reorganization

• B+-trees have a higher insertion time compared to indexed-sequential files

• B+-trees require periodic reorganization of the entire file

What is the main drawback of B-Tree indices compared to B+-Tree indices?

• B-Tree indices are easier to implement than B+-Tree indices

• B-Tree indices have a higher fan-out than B+-Tree indices

• B-Tree indices have a greater depth than B+-Tree indices

• B-Tree indices allow search-key values to appear multiple times

What is the benefit of using bitmap indices?

• Bitmap indices are particularly useful for queries on multiple keys

• Bitmap indices are useful for single attribute queries

• Bitmap indices require more space compared to traditional indices

• Bitmap indices are only applicable to numerical data

How are queries answered in R-Trees?

• By searching only the leaf nodes of the tree

• By searching all nodes of the tree sequentially

• By performing a binary search on the root node

• By recursively searching child nodes whose bounding boxes intersect the query region

What is the purpose of a log-structured merge tree in indexing?

• To reduce the number of I/O operations per record inserted

• To speed up range queries on spatial data

• To improve the performance of hash indices

• To store data in a single dimension

How are updates handled in LSM trees?

• Updates are handled using insert+delete operations

• Updates are handled by adding special 'update' entries

• Updates are not allowed in LSM trees

• Updates are handled by directly modifying the leaf nodes