WorksheetsUNIT I - DATABASE SYSTEM BASICS
Total questions: 50
Worksheet time: 25mins
Which of the following is the main purpose of a Database System?
Data redundancy
Data inconsistency
Data management and retrieval
Data isolation
The view of data that describes how the data is actually stored is the:
External view
Conceptual view
Internal view
Logical view
Which data model uses entities, attributes, and relationships?
Hierarchical model
Network model
Relational model
ER model
In the relational model, data is represented as:
Trees
Tables
Graphs
Hierarchies
Which key uniquely identifies each record in a table?
Foreign key
Primary key
Super key
Alternate key
Which of the following is NOT a component of DBMS architecture?
A) Storage manager
B) Query processor
C) Application program
Relational Algebra is a:
Procedural language
Non-procedural language
Object-oriented language
Natural language
Relational Calculus is a:
Procedural query language
Non-procedural query language
Programming language
None of these
Which SQL statement is used to extract data from a database?
GET
SELECT
EXTRACT
OPEN
A Trigger in SQL is:
A) A function executed manually
B) Automatically executed when an event occurs
C) Used to store procedures
D) A data type
Embedded SQL is used to:
Execute SQL from command line
Integrate SQL with programming languages
Perform system administration
Execute triggers
A schema defines:
Data values
Structure of the database
Indexes
Views
Which of these is a data definition language (DDL) command?
SELECT
UPDATE
CREATE
INSERT
Which command removes a table permanently?
DELETE
DROP
REMOVE
ERASE
A foreign key:
Must be unique
Refers to a primary key in another table
Has no relation to other keys
Is same as super key
ER diagram is used for:
Transaction control
Database design
Query execution
Security control
A weak entity set requires:
Partial key
Strong entity set
Both A and B
None
Functional dependency is a relationship between:
Two relations
Attributes of the same relation
Keys
Entities
Normalization is used to:
Increase redundancy
Reduce redundancy
Speed up queries
Create anomalies
First Normal Form (1NF) deals with:
Atomic values
Transitive dependency
Partial dependency
Multivalued dependency
A table is in 2NF if it is in 1NF and:
No partial dependency exists
No transitive dependency exists
Every determinant is a candidate key
It has only atomic values
A table in 3NF must be in 2NF and:
Remove transitive dependency
Remove partial dependency
Contain multivalued attributes
Have no foreign keys
Boyce-Codd Normal Form (BCNF) handles:
Transitive dependencies
Anomalies not handled by 3NF
Multivalued dependencies
Join dependencies
A table with multivalued dependency is normalized to:
2NF
3NF
4NF
5NF
Fifth Normal Form (5NF) removes:
Multivalued dependencies
Join dependencies
Transitive dependencies
Partial dependencies
Dependency preservation means:
All FDs are preserved in decomposition
All tables have primary keys
All data is preserved after normalization
None of the above
Non-loss decomposition ensures:
Data redundancy
No data loss during decomposition
Data inconsistency
Data replication
A transaction is:
A) A single SQL query
B) A logical unit of work
C) A physical operation
D) A rollback operation
29. ACID stands for:
Atomicity, Consistency, Isolation, Durability
Accuracy, Completeness, Integrity, Durability
Serializability ensures:
Concurrent execution is safe
Transactions execute serially
System crashes are avoided
Deadlocks are handled
Isolation level defines:
Access permissions
Degree to which transaction is isolated from others
Speed of execution
Storage format
A deadlock occurs when:
Transactions wait indefinitely for each other
System crashes
Data is lost
Rollback fails
Two-phase locking ensures:
Recoverability
Serializability
Deadlock avoidance
Atomicity
A log is used in recovery to:
Track data redundancy
Record changes for rollback
Create indexes
Control concurrency
Which of the following is a failure classification?
Transaction Failure
System Crash
Memory Allocation Error
Both A and B
A checkpoint is used to:
Mark a safe state for recovery
Stop all transactions
Remove deadlocks
Enforce integrity constraints
RAID stands for:
Random Access Integrated Disk
Redundant Array of Inexpensive Disks
Reorganized Access Indexed Database
None of these
Which file organization stores records sequentially?
Heap
Sequential
Hash
Indexed
A record is:
A) A collection of fields
B) A collection of tables
C) A data type
D) None
An index improves:
Storage efficiency
Query performance
Security
B+ Tree is used for:
Encryption
Indexing
Transaction control
Backup
Static hashing:
Uses fixed number of buckets
Uses dynamic buckets
Reorganizes data frequently
Is slower than dynamic hashing
Dynamic hashing:
Uses variable number of buckets
Uses fixed number of buckets
Doesn’t allow growth
Is obsolete
Query processing includes:
Parsing and translation
Optimization
Execution
All of these
Heuristic optimization uses:
Cost-based analysis
Rule-based transformations
Random execution
None
Cost-based optimization depends on:
Query syntax
Statistics about data such as table size and index availability
Number of users connected
Network bandwidth
A clustered index:
Doesn’t affect physical order
Determines physical order of records
Is same as primary key
Is slower than non-clustered
The primary file organization used by databases is:
Sequential
Indexed sequential
Hash-based
Linked
Query optimization aims to:
Rewrite SQL queries
Reduce query execution time
Increase redundancy
Modify indexes
In query execution, the final step is:
Query parsing
Plan selection
Query evaluation
Cost estimation
