WorksheetsDatabase Module - Quiz
Total questions: 50
Worksheet time: 25mins
Which of the following is TRUE about a database schema?
Changes frequently
Represents current data
Overall logical design
Physical storage only
Data independence is achieved mainly due to:
ER model
Three level architecture
SQL
Normalization
In ER model, a weak entity depends on:
Key attribute
Strong entity
Multivalued attribute
Derived attribute
Which operation is NOT closed in relational algebra?
Union
Projection
Join
Assignment
σsalary>5000(EMP) removes:
Columns
Rows
Tables
Keys
Division operator is mainly used for queries involving:
At least one
All values
None
Join
Relational calculus is:
Procedural
Record based
Non-procedural
Physical
RA and RC are equivalent in:
Syntax
Expressive power
Speed
Memory
Which SQL clause is executed last?
WHERE
GROUP BY
HAVING
SELECT
A view is stored as:
Table
Query
File
Index
If A → B and B → C, then A → C by:
Reflexivity
Augmentation
Transitivity
Decomposition
A relation is in 2NF if:
No transitive dependency
No partial dependency
No FD
No MVD
BCNF violation occurs when:
LHS is key
RHS is key
LHS is not a super key
RHS is non-prime
4NF removes:
FD
Partial dependency
MVD
JD
Which is lossless decomposition condition?
Common attribute is key
Common attribute is FD
No common attribute
Separate keys
A schedule is conflict serializable if its precedence graph is:
Cyclic
Acyclic
Complete
Directed
Cascading rollback occurs due to:
Dirty read
Phantom read
Deadlock
Starvation
Strict 2PL avoids:
Deadlock
Cascading aborts
Starvation
Phantom reads
Timestamp ordering avoids:
Deadlock
Starvation
Cascading
Logging
Deadlock requires:
Circular wait
Preemption
Sharing
No hold
WAL stands for:
Write After Log
Write Ahead Log
Write Around Log
Write All Log
Shadow paging uses:
Log file
Two page tables
Locks
Index
Heap file organization is best for:
Range queries
Random inserts
Sorted access
Indexing
Ordered file organization helps in:
Insert
Delete
Range queries
Update
Dense index contains:
One entry per block
One entry per record
One entry per table
One entry per key range
Sparse index requires:
Ordered file
Heap file
Hash file
Random file
B+ tree data pointers are in:
Root
Internal nodes
Leaf nodes
All nodes
Height of B+ tree depends on:
Records
Keys
Fan out
Blocks
Static hashing suffers from:
Overflow buckets
Sorting
Indexing
Joins
Linear hashing is:
Static
Dynamic
Ordered
Indexed
Query cost is mainly measured by:
CPU time
I/O operations
RAM
Network
Selection pushdown is used in:
ER model
Query optimization
Indexing
Normalization
Which join is costliest?
Nested loop
Merge join
Hash join
Index join
Which anomaly is removed by normalization?
Update anomaly
Deadlock
Crash
Lock
A super key:
Minimal key
Unique identifier
Foreign key
Composite key
Candidate key is:
Minimal super key
Any key
Foreign key
Prime key
Foreign key ensures:
Uniqueness
Referential integrity
Functional dependency
Normalization
Which is NOT a DDL command?
CREATE
DROP
INSERT
ALTER
HAVING is used with:
WHERE
GROUP BY
SELECT
ORDER BY
Which anomaly occurs due to redundancy?
Update
Deadlock
Crash
Lock
Phantom problem occurs in:
Dirty read
Range query
Write write conflict
Lost update
Multiversion concurrency control uses:
Locks
Timestamps
Multiple copies
Logs
Checkpoint in recovery is used to:
Delete logs
Reduce recovery time
Increase speed
Avoid crash
Log records are written to:
Disk after commit
Disk before data
Memory only
Cache only
Which dependency is removed in 3NF?
Partial
Transitive
MVD
JD
Natural join is:
Cartesian + Selection
Union + Selection
Projection + Join
Division + Join
Rename operator is:
σ
π
ρ
÷
TRC uses:
Domain variables
Tuple variables
Keys
Tables
Domain relational calculus uses:
Tuple variables
Domain variables
Keys
FDs
The main goal of query optimizer is to:
Increase joins
Reduce I/O cost
Increase tables
Reduce normalization
