Which of the following is / are NOT CORRECT statement ? (A) The first record…
2023
Which of the following is / are NOT CORRECT statement ?
(A) The first record in each block of the data file is known as actor record.
(B) Dense index has index entries for every search key value in the data file.
(C) Searching is harder in the B+ tree than B - tree as the all external nodes linked to each other.
(D) In extendible hashing the size of directory is just an array of 2d-1, where d is global depth.
Choose the correct answer from the options given below :
- A.
(A), (B) and (C) Only
- B.
(A), (C) and (D) Only
- C.
(A), (B) and (D) Only
- D.
(A), (B), (C) and (D) Only
Attempted by 109 students.
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Correct answer: B
Answer: (A), (C) and (D) are NOT correct; (B) is correct.
Reasoning:
(A) The statement that the first record in each block is called an "actor record" is incorrect. There is no standard DBMS term "actor record" for the first record in a block, so this wording is wrong.
(B) The statement about dense index is correct: a dense index has an index entry for every search key value (or equivalently for every record).
(C) The claim that searching is harder in a B+ tree because all external (leaf) nodes are linked is incorrect. Linking leaf nodes actually facilitates range queries and does not make point searches inherently harder than in a B-tree; search complexity is comparable and often the same order.
(D) The directory size in extendible hashing is 2^d (two to the power d), where d is the global depth. The given expression is incorrect, so this statement is not correct.
Final : The NOT CORRECT statements are (A), (C) and (D).