what are the advantages of a b+ tree over a hash index.

Question

Question

Answer 1

Answer #1

B-Tree Indexes

B-Tree Indexes are suitable for range queries/range scans since the keys are ordered. For example, the following types of queries will benefit from a typical B-Tree Index structure on “SALARY” column.
- “SELECT * FROM T WHERE SALARY>5000 AND SALARY<10000”
- “SELECT * FROM T WHERE SALARY>5000”;
- The result set for such queries will contain rows in sorted order since the index stores the keys in order.
The above point about suitability of B-Tree Indexes for range scans is valid for both UNIQUE and NON-UNIQUE Indexes.
It is not the case that B-Tree Indexes are not suitable point lookups. We can definitely use B-Tree indexes for point lookups but hash indexes are usually more efficient for such workloads.
- The reason is extra I/O done in B-Tree indexes from the root block -> branch block -> leaf block to get to the data of interest whereas the cost of same operation with hash index is likely to be amortized O(1) provided the hash index is properly sized and handles collisions appropriately.
B-Tree Indexes are efficient for both full-key and prefix-key matching queries.
B-Tree indexes can be kept of optimal height to minimize the number of I/Os and the scalability problem mentioned above for hash indexes is not really a concern for B-Tree indexes.

Answer 2

Similar Homework Help Questions

[Index structure: B+ tree and B tree] (b). B+ tree index structure is said to be...

[Index structure: B+ tree and B tree] (b). B+ tree index structure is said to be an improvement of B tree index structure. The most important distinction between them is that data record pointers exist in both internal and leaf nodes (i.e., blocks) for a B tree whereas only in the leaf nodes for a B+ tree. Explain why this distinction would make B+ tree a more efficient structure (in terms of index search speed) overall than a B tree...
Tree & Hash Table & Heap Use the following integer keys 73, 58, 91, 42, 60,...

Tree & Hash Table & Heap Use the following integer keys 73, 58, 91, 42, 60, 130, 64, 87 to perform the followings: a) Binary Search Tree - Draw a binary search tree - Retrieve the integers keys in post-order - Retrieve the integers keys in pre-order - Draw a binary search tree after node 58 is deleted b) Create a Hash Table using the methods described below. Show the final array after all integer keys are inserted. Assumes that...
What are the main characteristics of a binary search tree? In your opinion, what advantages does...

What are the main characteristics of a binary search tree? In your opinion, what advantages does a binary search tree have over a linked list or an array? Assuming you want to create a binary search tree of integers, draw the resulting tree if the integers input were as follows : 25 43 12 20 5 50 30

Tree & Hash Table & Heap Use the following integer keys 73, 58, 91, 42, 60, 130, 64, 87 to perform the followings: a) Binary Search Tree - Draw a binary search tree - Retrieve the integers ke...

Tree & Hash Table & Heap Use the following integer keys 73, 58, 91, 42, 60, 130, 64, 87 to perform the followings: a) Binary Search Tree - Draw a binary search tree - Retrieve the integers keys in post-order - Retrieve the integers keys in pre-order - Draw a binary search tree after node 58 is deleted b) Create a Hash Table using the methods described below. Show the final array after all integer keys are inserted. Assumes that...
Summarize the advantages and disadvantages of the Ø-index approach over the Green Ampt method for estimating...

Summarize the advantages and disadvantages of the Ø-index approach over the Green Ampt method for estimating infiltration losses for a storm. (clear writing or typing)
Given the hash function: H(key) = key/2; Hash table size = 7 and index = H(key)%...

Given the hash function: H(key) = key/2; Hash table size = 7 and index = H(key)% Hash table size Show how the hash table below looks after adding the following (key, value) pairs, (illustrate your strategy for collision handling) (3000, “A”) (3232, “B”) (1223, “C”) (4569, “K”) (6767, “F”) (1234, “P”) (2324, “F”) (3422, “G”) (1231, “R”) index Key Value 0 1 2 3 4 5

Array list, Linkedlist, Stack, Queue, binary tree, hash table What are their respective logical and physical...

Array list, Linkedlist, Stack, Queue, binary tree, hash table What are their respective logical and physical / storage structures? i am asking this question note what are their respective logical and physical / storage structures?
List the contents of a hash table of SIZE 10 filled using chaining Use the hash function: index= ...

Java question need help For the data elements can be item1, item2, item3 ,item4.... etc. List the contents of a hash table of SIZE 10 filled using chaining Use the hash function: index= ((string. length() * 3) The data elements are: Add the elements in the order given List the elements contained in each "bucket" (if any) Elements should be chained in the order added, separated by a comma and a space If an index is empty enter the word...
Assume that you have built a dense B+-tree index on SSN, and the B+-tree's leaf nodes...

Assume that you have built a dense B+-tree index on SSN, and the B+-tree's leaf nodes contain record ids pointing to data records in data file. Assume 10-byte long. Assume also that you built the tree by using bulk loading so that the nodes at each level were filled up as much as possible. 4. a. b. How many levels does the resulting tree have? For each level of the tree, how many nodes are at that level? How many...

1. Given a hash table with size 10, hash function is hash(k) = k % 10,...

1. Given a hash table with size 10, hash function is hash(k) = k % 10, and quadratic probing strategy is used to solve collisions. Please insert the keys 19, 68, 59, 20, 32, 88, 56 in the hash table. 2. Let T be a binary tree with 31 nodes, what is the smallest possible height of T? What is the largest possible height of T?