# Recent questions tagged indexing 2 votes
1 answer
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A data file consisting of $1,50,000$ student-records is stored on a hard disk with block size of $4096$ bytes. The data file is sorted on the primary key $\textrm{RollNo}$. The size of a record pointer for this disk is $7$ bytes. Each student-record has ... disk. Assume that the records of data file and index file are not split across disk blocks. The number of blocks in the index file is ________
17 votes
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Consider a database implemented using $\text{B+}$ tree for file indexing and installed on a disk drive with block size of $\text{4 KB}$. The size of search key is $\text{12 bytes}$ and the size of tree/disk pointer is $\text{8 bytes}$. ... memory. Consider that each record fits into one disk block. The minimum number of disk accesses required to retrieve any record in the database is _______
2 votes
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The minimum number of nodes (both leaf and non-leaf) of $B^{+}$ tree index required for storing $5500$ keys and order of $B^{+}$ tree is $8$________________(order is max pointers a node can have) See here first level should be divide by $7$ $2nd$ levelshould divide by ... each $7$ pointer of 1st level has $8$ pointer in 2nd level. Am I missing something?? But in ans they divided by only $8$ :(
2 votes
1 answer
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Consider the following statement below: $A)$ A clustered index may be either sparse or dense. $B)$ Every $B^{+}$ tree index is dense. Which of the above statement is true? Is clustering Index can be dense. Dense means non-ordering field, but clustering field should be ordering field right??
1 vote
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Construct a $B^+$-tree for the following set of key values: $(2, 3, 5, 7, 11, 17, 19, 23, 29, 31)$ Assume that the tree is initially empty and values are added in ascending order. Construct B+-trees for the cases where the number of pointers that will fit in one node is as follows: a. Four b. Six c. Eight
1 vote
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Is it possible in general to have two primary indices on the same relation for different search keys ? Explain your answer.
0 votes
1 answer
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What is the difference between a primary index and a secondary index ?
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Since indices speed query processing, why might they not be kept on several search keys ? List as many reasons as possible.
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When is it preferable to use a dense index rather than a sparse index ? Explain your answer.
1 vote
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Q Consider a relation R(a, b, c) ordered on a non-key attribute b, and an index is maintained on attribute c. To evaluate the following expression, which is a better order of operation? σ(b= abc'∧c=12)(R) A. First filter tuples using index on c and then ... First search tuples for the given value of b and then use index on c C. The order of operation does not matter D. Insufficient data to answer
2 votes
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among primary index, secondary index, clustered index which index are dense or sparse or both?
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I am confused about indexing being densed or sparse, Read a lot of answer but can't figure out Primary Index is always sparse : since indexing is done of key attribute and records(files) are ordered so we create index only for anchor of the block(group of records). ... record and is only for some records. Please correct me If I am wrong at some point and If I am right then please comment.
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Can anyone suggest me any useful source from where I can read b+ tree insertion and deletion?
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​​​​​​​A clustering index is defined on the fields which are of type non-key and ordering non-key and non-ordering key and ordering key and non-ordering
3 votes
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suppose that in a file organization record size(R)=150 bytes , block size (B)=512 bytes. there are totally 30000 records. the data field on which indexing is done is 9 bytes and block pointer size is 7 bytes how many block access will be needed to access a data item in case of single level primary indexing?
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18
Can anyone explain this in detail???
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Consider a $B^+$ tree , in which order of internal nodes is 4 and order of leaf nodes is 3. The order of internal nodes is the maximum number of tree pointers in each internal node and the order of leaf node is the maximum number of data items that can be stored in each ... below way and I got 3 splits, assuming B+ tree with left biasing. But the answer is given to be 8. Have I made any mistake?
1 vote
2 answers
20
what is the minimum and maximum number of keys for non-leaf nodes and leaf nodes for B+ Tree of order p?
0 votes
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21
can anyone share some good resources fot B+ tree deletion?
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2 votes
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I have two doubts here (1)Doubt1-The number of blocks needed to store file must be 3000 and not 2930. Record organisation is unspanned and so 1 block can contain only 10 records. Here in solution, they are trying to fit bytes into blocks and not records ... they didn't tell, for purpose of optimisation we can consider multi-level indexing with primary index. What should be the correct answer here?
2 votes
1 answer
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How to prove that if same size blocks are allocated to B trees and B+ trees then:- No. of index nodes in B tree >= No. Of index nodes in B+ tree
1 vote
1 answer
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Block size 1000B records are of size 100B of which 12B are the key field and pointer of size 8B. a file consist of 10000 records 1.the number of blocks required for a sparse index on this file? 2.the number of blocks required for for a dense index on this file