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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The set of ________ in a precedence graph consists of all the transactions participating in the schedule(a) Vertices(b) Edges(c) Directions(d) None of the mentioned |
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Answer» Correct choice is (a) Vertices Explanation: The set of vertices in a precedence graph consists of all the transactions participating in the schedule. Precedence graph is a simple and efficient way of determining conflict serializability of the schedule. |
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| 2. |
Which of the following is a measure of reliability of a disk?(a) Seek time(b) Average latency time(c) Mean time to failure(d) Average seek time |
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Answer» Right choice is (c) Mean time to failure To elaborate: The mean time to failure is the measure of the reliability of a disk. It gives the mean of the times that most disks last. |
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| 3. |
Which of the following is a part of the Magnetic disk assembly?(a) Spindle(b) Read write head(c) Arm(d) All of the mentioned |
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Answer» Right option is (d) All of the mentioned The explanation is: In a magnetic disk assembly, Spindle is the central cylindrical rod, Read write head is used to read and write data and the arm is used to hold the magnetic disk. |
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| 4. |
If on every legal database instant, the two expressions generate the same set of tuples, the expressions are called as(a) Equal(b) Equivalent(c) Similar(d) Identical |
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Answer» Right option is (b) Equivalent Easy explanation: If on every legal database instant, the two expressions generate the same set of tuples, the expressions are called as Equivalent relational algebra expressions. The order of the tuples is completely irrelevant for equivalency. |
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| 5. |
Which of the following joins preserves the tuples of the relation on the left side of the operator?(a) Left outer join(b) Natural join(c) Right outer join(d) None of the mentioned |
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Answer» Right choice is (a) Left outer join Explanation: Left outer join and full outer join both preserve the tuples on the left side of the operator. |
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| 6. |
If a schedule S can be transformed into a schedule S’ by a series of swaps of non-conflicting instructions, then S and S’ are(a) Non conflict equivalent(b) Equal(c) Conflict equivalent(d) Isolation equivalent |
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Answer» Right option is (c) Conflict equivalent The best I can explain: If a schedule S can be transformed into a schedule S’ by a series of swaps of non-conflicting instructions, then S and S’ are conflict equivalent. Not all serial schedules are conflict equivalent to each other. |
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| 7. |
Search algorithms that use an index are referred to as _________(a) Index scans(b) Search scans(c) Primary scans(d) Equality scans |
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Answer» The correct choice is (a) Index scans Easiest explanation: Search algorithms that use an index are called as index scans. We use the selection predicate to guide us through the choice of index to use in processing the query. |
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| 8. |
The blocks residing on the disk are referred to as ___________(a) Physical blocks(b) Buffer blocks(c) Disk blocks(d) Disk buffer |
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Answer» Correct choice is (a) Physical blocks Explanation: The blocks residing on the disk are referred to as physical blocks. The blocks residing temporarily in the main memory are referred to as buffer blocks. |
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| 9. |
If the operations do not wait to produce tuples, then it is called as _________(a) Demand driven pipeline(b) Producer driven pipeline(c) Query driven pipeline(d) None of the mentioned |
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Answer» The correct option is (b) Producer driven pipeline Explanation: If the operations do not wait to produce tuples, then it is called as producer driven pipeline. IT does not wait to produce tuples but it produces tuples eagerly. |
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| 10. |
A ________ ensures that any conflicting read and write operations are executed in timestamp order(a) Organizational protocol(b) Timestamp ordering protocol(c) Timestamp execution protocol(d) 802-11 protocol |
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Answer» Right option is (b) Timestamp ordering protocol To explain: A timestamp ordering protocol ensures that any conflicting read and write operations are executed in timestamp order. |
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| 11. |
Insertion of a large number of entries at a time into an index is referred to as _______ of the index.(a) Bulk loading(b) Mass insertion(c) Quick insertion(d) Quick loading |
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Answer» Correct option is (a) Bulk loading To elaborate: Insertion of a large number of entries at a time into an index is referred to as bulk loading of the index. This reduces the time complexity as multiple entries are loaded at the same time. |
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| 12. |
What are the leaf nodes in a B+ tree?(a) The topmost nodes(b) The bottommost nodes(c) The nodes in between the top and bottom nodes(d) None of the mentioned |
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Answer» The correct choice is (b) The bottommost nodes Easy explanation: The bottommost nodes that mark the end of a tree are known as the leaf nodes in a B+ tree. |
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| 13. |
The default timestamp ordering protocol generates schedules that are(a) Recoverable(b) Non-recoverable(c) Starving(d) None of the mentioned |
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Answer» The correct answer is (b) Non-recoverable Explanation: The timestamp ordering protocol generates schedules that are non-recoverable. But it can be extended to make the schedules recoverable. |
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| 14. |
State true or false: The fanout of nodes can be increased by using a technique called _________(a) Prefix compression(b) Postfix compression(c) Prefix expansion(d) Postfix expansion |
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Answer» The correct answer is (a) Prefix compression Best explanation: The fanout of nodes can be increased by using a technique called prefix compression. In this, we do not store the entire value of the search key at the node. We only store the prefix of the search key. |
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| 15. |
A search key containing more than one attribute is called a _________ search key(a) Multiple(b) Multilevel(c) Composite(d) Primary |
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Answer» Correct choice is (b) Multilevel The explanation: A search key containing more than one attribute is called as a composite search key. The structure of the index is the same as that of any other index, the only difference being that it is not a single search attribute but a list of attributes. |
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| 16. |
If a relation can have more than one record containing the same search key value, the search key is said to be a __________(a) Unique search key(b) Non unique search key(c) Multiple search key(d) Identical search key |
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Answer» The correct option is (b) Non unique search key For explanation: If a relation can have more than one record containing the same search key value, the search key is said to be a non-unique search key. A problem with non-unique search keys is inefficiency during delete operations. |
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| 17. |
If K denotes the set of all the search key values, and B denotes the set of all bucket addresses, a function from K to B is called as __________(a) Bucket function(b) Address function(c) Hash function(d) Search function |
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Answer» Correct answer is (c) Hash function To elaborate: If K denotes the set of all the search key values, and B denotes the set of all bucket addresses, a function h from K to B is called as the hash function. It determines which bucket should contain the data in question. |
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| 18. |
Some buckets are assigned more records than the others which causes bucket overflow, this condition is called as ________(a) Bucket sufficiency(b) Bucket insufficiency(c) Bucket skew(d) Bucket normalcy |
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Answer» Correct option is (c) Bucket skew To explain: Some buckets are assigned more records than the others which causes bucket overflow, this condition is called as Bucket skew. Skew occurs if multiple records have the same search key or if the given hash function is non uniform. |
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| 19. |
If the transaction can no longer continue with its normal execution because of some internal condition, it is called as a _________(a) Logical error(b) System error(c) System crash(d) None of the mentioned |
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Answer» The correct answer is (a) Logical error To elaborate: If the transaction can no longer continue with its normal execution because of some internal condition, it is called as a logical error such as bad input, data not found, overflow or resource limit exceeded. |
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| 20. |
During the _________ phase the validation test is applied to the transaction(a) Read phase(b) Validation phase(c) Write phase(d) None of the mentioned |
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Answer» Right option is (b) Validation phase The explanation is: During the validation phase, the validation test is applied to the transaction. This determines whether the transaction is allowed to proceed or not without causing a violation of serializability. |
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| 21. |
The _________ requires each transaction executes in two or three different phases in its lifetime(a) Validation protocol(b) Timestamp protocol(c) Deadlock protocol(d) View protocol |
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Answer» Correct choice is (a) Validation protocol To explain I would say: The validation protocol requires each transaction to execute in two or three different phases in its lifetime depending on whether it is a read only or an update transaction. |
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| 22. |
In a __________ , we obtain the address of the disk block containing a desired record directly by computing a function on the search key value of the record(a) Hash file organization(b) Hash index organization(c) Hashing address(d) None of the mentioned |
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Answer» The correct option is (a) Hash file organization The explanation is: Hashing can be used for 2 different purposes, hash file organization and hash index organization. In a Hash file organization, we obtain the address of the disk block containing a desired record directly by computing a function on the search key value of the record. |
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| 23. |
What is a bucket overflow?(a) When a bucket does not have enough space(b) There are insufficient buckets(c) When Bucket skew occurs(d) All of the mentioned |
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Answer» Right choice is (d) All of the mentioned Explanation: Bucket overflow can occur in many ways. When a bucket does not have enough space, there are insufficient buckets, when a bucket skew occurs. |
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| 24. |
A transaction that performs only one operation is called as a _________(a) Partial schedule(b) Complete schedule(c) Dependent schedule(d) Independent schedule |
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Answer» Right answer is (a) Partial schedule To elaborate: A transaction that performs only one operation is called as a partial schedule because we don’t include commit or rollback operations on them. |
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| 25. |
In a __________ we organize the search keys, with their associated pointers, into a hash file structure(a) Hash file organization(b) Hash index organization(c) Hashing address(d) None of the mentioned |
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Answer» Correct option is (b) Hash index organization Explanation: Hashing can be used for 2 different purposes, hash file organization and hash index organization. In a hash index organization, we organize the search keys, with their associated pointers, into a hash file structure. |
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| 26. |
The unique identifier of the transaction that performed the write operation is called as _______(a) Transaction identifier(b) Data-item identifier(c) Old value(d) New value |
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Answer» Right answer is (a) Transaction identifier For explanation I would say: The unique identifier of the transaction that performed the write operation is called as transaction identifier. This is a field in the update log record. |
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| 27. |
The time it takes to delete a data item is called as _________(a) Insertion time(b) Deletion time(c) Time overhead(d) Access time |
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Answer» The correct choice is (b) Deletion time Explanation: The time it takes to delete a data item is called as deletion time. This value includes finding the item to be deleted and the time taken to update the index structure. |
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| 28. |
________ deletes a data item from a database(a) Delete(Q)(b) Insert(Q)(c) Drop(Q)(d) None of the mentioned |
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Answer» Right option is (a) Delete(Q) Best explanation: Delete(Q) deletes a data item from a database. Insert(Q) inserts a new data item Q into the database and assign Q an initial value. |
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| 29. |
If an index entry appears for every search key value in the file, it is called as ________(a) Dense key(b) Dense index(c) Sparse key(d) Sparse index |
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Answer» Correct option is (b) Dense index For explanation: In a dense index, an index entry appears for every search key value in the file. In a dense clustering index, the index record contains the search-key value and a pointer to the first data record with that search-key value. |
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| 30. |
What is a multitable clustering file organization?(a) It stores related records of two or more relations in each block(b) It stores related data about the relations in each block(c) It links each and every block by introducing an external attribute(d) None of the mentioned |
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Answer» Correct choice is (a) It stores related records of two or more relations in each block Best explanation: A multitable clustering file organization stores the related records of two or more relations in each block. This allows us to read records that satisfy a join condition by using one block read. |
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| 31. |
If an index entry appears for only some of the search key values in the file, it is called as ________(a) Dense key(b) Dense index(c) Sparse key(d) Sparse index |
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Answer» Correct answer is (d) Sparse index Easiest explanation: In a sparse index, an index entry appears for only some of the search key values. Sparse indices can be used only if the relation is stored in the sorted order of the search key i.e. if the index is a clustering index. |
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| 32. |
The dependency rules specified by the database designer are known as _______(a) Designer dependencies(b) Database rules(c) Functional dependencies(d) None of the mentioned |
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Answer» Right choice is (c) Functional dependencies For explanation I would say: The dependency rules specified by the database designer are known as functional dependencies. The normal forms are based on functional dependencies. |
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| 33. |
If there is a hardware malfunction or a bug in the database that causes the loss of content of volatile storage, it is called as ________(a) Logical error(b) System error(c) System crash(d) None of the mentioned |
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Answer» Right answer is (c) System crash The best I can explain: If there is a hardware malfunction or a bug in the database that causes the loss of content of volatile storage, it is called as a system crash. The data in the non-volatile storage remains intact and it is not corrupted. |
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| 34. |
The value of the data item prior to the write is called as _________(a) Transaction identifier(b) Data-item identifier(c) Old value(d) New value |
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Answer» Right answer is (c) Old value To explain I would say: The value of the data item prior to the write is called as old value. This is stored in the update log record. |
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| 35. |
A transaction is made to wait until all ________ locks held on the item are released(a) Compatible(b) Incompatible(c) Concurrent(d) Equivalent |
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Answer» Correct option is (a) Compatible To explain I would say: A transaction is made to wait until all compatible locks held on the item are released. This ensures that no other transaction is concurrently accessing the same item. |
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| 36. |
What is sequential file organization?(a) Any record can be placed wherever there is a space for the record(b) Records are stored in a sequential order according to a search key(c) A hash function is computed on some attribute and that decides the block(d) None of the mentioned |
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Answer» Right option is (b) Records are stored in a sequential order according to a search key For explanation: Sequential file organization means that Records are stored in a sequential order according to a search key. The records are ordered. |
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| 37. |
What is a search key in sequential file organization?(a) A number assigned to each record(b) Necessarily the primary key(c) Any attribute or a set of attributes(d) None of the mentioned |
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Answer» The correct choice is (c) Any attribute or a set of attributes Explanation: A search key in sequential file organization is any attribute or a set of attributes that need not be a primary key or even a superkey. |
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| 38. |
The most widely used structure for recording database modification is called as _______(a) Log(b) List(c) Queue(d) Stack |
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Answer» The correct option is (a) Log Explanation: The most widely used structure for recording database modification is called as a log. The log is a sequence of log records recording all the update activities in the database. |
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| 39. |
If a transaction does not modify the database until it has committed it is said to use a _______ modification technique(a) Deferred(b) Immediate(c) More than one of the mentioned(d) None of the mentioned |
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Answer» Right answer is (a) Deferred Easiest explanation: If a transaction does not modify the database until it has committed it is said to use a deferred modification technique. Deferred modification has the overhead that transactions need to make local copies of all updated data items. |
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| 40. |
If a transaction Ti may never make progress, then the transaction is said to be ____________(a) Deadlocked(b) Starved(c) Committed(d) Rolled back |
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Answer» Right choice is (b) Starved To explain: If a transaction Ti may never make progress, then the transaction is said to be starved. |
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| 41. |
If a transaction may release locks but may not obtain any locks, it is said to be in ______ phase(a) Growing phase(b) Shrinking phase(c) Deadlock phase(d) Starved phase |
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Answer» The correct choice is (b) Shrinking phase For explanation: If a transaction may release locks but may not obtain any locks, it is said to be in shrinking phase. Shrinking phase is a phase in two phased locking protocol. |
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| 42. |
Which of the following is a disadvantage of the dynamic hashing structure(a) Buckets can be allocated dynamically(b) Lookup involves additional level of indirection(c) It involves a lesser space overhead(d) Hash structure can be modified dynamically |
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Answer» The correct answer is (b) Lookup involves additional level of indirection The explanation: In dynamic hashing, lookup involves an additional level of indirection. The rest of the options are the advantages of dynamic hashing. |
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| 43. |
The form of dynamic hashing that avoids the additional level of indirection is called as _________(a) Linear hashing(b) Static hashing(c) Directive hashing(d) Indirective hashing |
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Answer» The correct answer is (a) Linear hashing The best explanation: The form of dynamic hashing that avoids the additional level of indirection is called as Linear hashing. This has more overflow buckets than extendable hashing. |
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| 44. |
Optimizers use __________ to reduce the cost of optimization.(a) Analyzers(b) Statistics(c) Heuristics(d) Caches |
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Answer» Correct answer is (c) Heuristics Explanation: Cost based optimizers may be expensive as exploring space of all possible plans might prove to be costly. So, optimizers use heuristics to reduce the cost of optimization. |
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| 45. |
Dynamic hashing allows us to?(a) Accommodate the growth of the database(b) Accommodate the shrinkage of the database(c) Allows modification of hash function(d) All of the mentioned |
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Answer» Correct answer is (d) All of the mentioned To explain: Dynamic hashing allows us to accommodate the growth of the database and the shrinkage of the database by allowing us to change the hash function dynamically. |
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| 46. |
Dynamic hashing is also called as _________(a) Extended hashing(b) Extendable hashing(c) Static hashing(d) Movable hashing |
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Answer» Correct choice is (b) Extendable hashing To elaborate: Dynamic hashing is also called as extendable hashing because it can accommodate the growth and shrinkage of the database. |
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| 47. |
In ________ no two aborts occur unless two concurrent transactions update the same data item.(a) Multiversion scheme(b) Timestamp protocol(c) Lock based protocol(d) Snapshot isolation |
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Answer» The correct option is (d) Snapshot isolation Easy explanation: In snapshot isolation no two aborts occur unless two concurrent transactions update the same data item. This makes snapshot isolation attractive but it does not ensure serializability. |
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| 48. |
What is hashing file organization?(a) Any record can be placed wherever there is a space for the record(b) Records are stored in a sequential order according to a search key(c) A hash function is computed on some attribute and that decides the block(d) None of the mentioned |
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Answer» The correct choice is (c) A hash function is computed on some attribute and that decides the block To explain: Hashing file organization means that a hash function is computed on some attribute and that decides the block. The result of the hash function specifies which block of the file the record should be placed in. |
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| 49. |
If the database modifications occur while the transaction is still active, the transaction is said to use the __________ modification technique(a) Deferred(b) Immediate(c) More than one of the mentioned(d) None of the mentioned |
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Answer» Correct option is (b) Immediate Best explanation: If the database modifications occur while the transaction is still active, the transaction is said to use the immediate modification technique. Deferred modification has overhead whereas immediate modification doesn’t have any overhead. |
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| 50. |
Which of the following is a variant of snapshot isolation(a) First committer wins(b) First updater wins(c) More than one of the mentioned(d) None of the mentioned |
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Answer» Correct option is (c) More than one of the mentioned The best I can explain: First committer wins and first updater wins are two different variations of snapshot isolation. |
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