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WorksheetsDistributed Database Systems MCQs 1-7
Total questions: 40
Worksheet time: 20mins
What is a Distributed Database System (DDBS)?
A single database stored on one server
Multiple, logically related databases connected over a network
A backup system for centralized databases
A local database for offline access
Which of the following is not an advantage of distributed databases?
Scalability
Improved reliability
Simplicity of management
Faster access for local users
What is the primary goal of data fragmentation?
To hide data from users
To improve performance and availability
To increase database redundancy
To minimize storage space
In horizontal fragmentation, a relation is divided based on:
Columns
Rows
Tables
Keys
Which two properties can always be guaranteed in a distributed system according to the CAP theorem?
Consistency and Availability
Consistency and Partition Tolerance
Availability and Partition Tolerance
Only one property at a time
What distinguishes a client–server architecture from a P2P architecture?
Client–server uses no servers
P2P allows nodes to act as both clients and servers
Client–server offers no scalability
P2P requires central coordination between the client–server
In a homogeneous DDBMS, all nodes:
Have different DBMS and schemas
Share the same DBMS and schema
Operate independently without coordination
Use unrelated data models
Which type of fragmentation divides a relation into subsets of columns?
Vertical
Horizontal
Mixed
Allocated
What is the key advantage of Shared-Nothing Architecture (SNA)?
Centralized control
Shared memory for faster processing
High scalability and fault isolation
Redundant hardware sharing
In master–slave replication, which database handles write operations?
Slave
Both
Master
Backup node
In a multi-tier architecture, the “logic tier” is primarily responsible for:
Storing and retrieving data
User interaction and presentation
Processing business rules and logic
Managing client authentication
Which replication strategy copies only a subset of a database?
Full replication
Partial replication
Sharding
Snapshot replication
Which CAP theorem trade-off is most suitable for social media applications?
CP (Consistency + Partition Tolerance)
AP (Availability + Partition Tolerance)
CA (Consistency + Availability)
None of the above
Which scenario best demonstrates horizontal fragmentation?
Splitting CUSTOMER table into “Name” and “Address” columns
Storing product catalog copies in all sites
Dividing CUSTOMER table into Luzon, Visayas, and Mindanao rows
Splitting database tables by data type
What is the main challenge of maintaining data consistency in asynchronous replication?
High latency due to synchronous updates
Data changes may not immediately appear in replicas
Network partitions reduce availability
Writes are blocked until all replicas confirm
A distributed system that prioritizes correctness over availability during network failures is a:
CP system
AP system
CA system
Peer-to-Peer system
Which replication configuration requires acknowledgment from at least one replica before committing a transaction?
Asynchronous
Semi-synchronous
Full replication
Partial replication
Which type of DDBMS supports nodes with different DBMS software and schemas?
Homogeneous
Heterogeneous
Parallel
Shared-Nothing
Why can’t CA systems exist in a truly distributed environment?
Network partitions are inevitable
They use only one node
They require redundant schemas
They are slower than AP systems
Which statement about hybrid replication is correct?
It replicates the entire database at all times
It combines multiple replication methods to meet specific goals
It requires a homogeneous DDBMS setup
It only applies to peer-to-peer architectures
What is the main purpose of a Distributed Database System (DDBS)?
To centralize all data in one physical location
To distribute logically related databases across multiple sites while appearing as one system
To back up a single database for fault recovery
To encrypt data across multiple databases
Which of the following is not a motivation for distributed databases?
Reliability
Autonomy
Complexity
Scalability
In distributed query processing, which optimization strategy reduces data transfer between sites?
Projection expansion
Predicate pushdown and semijoin strategy
Centralized query execution
Delayed join evaluation
The main goal of query decomposition in distributed query processing is to:
Encrypt data for security
Break SQL queries into site-specific subqueries for parallel execution
Merge different database schemas into site-specific subqueries for parallel execution
Convert data into JSON format
What major problem does the Two-Phase Commit (2PC) protocol face?
It cannot ensure atomicity
It may cause blocking if the coordinator fails
It doesn’t communicate with participants
It ignores concurrency control
Compared to 2PC, the Three-Phase Commit (3PC) protocol:
Removes the need for coordinators to increase blocking and worsen fault tolerance
Adds an extra phase to reduce blocking and improve fault tolerance
Reduces communication cost
Allows transactions to commit independently
In distributed concurrency control, what is one advantage of timestamp ordering over locking?
Allows higher transaction priority regardless of timestamp
Eliminates deadlocks since no locks are used
Avoids transaction rollbacks completely
Uses fewer timestamps for faster processing
Which condition must be present for a deadlock to occur in a distributed system?
High network latency
Mutual exclusion of resources
Unbalanced query load
Redundant data replication
Which deadlock detection approach avoids a single point of failure by letting all nodes participate?
Centralized detection
Distributed detection
Banker’s algorithm
In the CAP theorem, a distributed database that continues operation despite network partitioning but allows temporary inconsistencies is an example of:
CA system
CP system
AP system
ACID system
What are Enhanced Database Models designed to address?
Faster network communication
Complex and unstructured data beyond simple tables
File compression
Improved data encryption
Which of the following is not a limitation of the traditional relational model?
Difficulty handling multimedia data
Inability to represent hierarchies naturally
Lack of support for fixed structures like rows and columns
Poor handling of unstructured data
Which database model stores data as objects containing both attributes and methods?
RDBMS
OODBMS
ORDBMS
NoSQL
In an OODBMS, what ensures that each object is uniquely identifiable?
Object Query Language (OQL)
Object Identifier (OID)
Primary Key
Foreign Key
Which concept in OODBMS allows a subclass to inherit attributes and behaviors from a superclass?
Encapsulation
Inheritance
Polymorphism
Aggregation
What is the purpose of Object Query Language (OQL)?
To store large binary files
To query objects instead of tables
To translate SQL to XML
To create primary keys for objects
What best describes an Object-Relational Database Management System (ORDBMS)?
Fully object-based with no tables
Combines relational structure with object-oriented features
A database without SQL support
Used only for multimedia storage
In ORDBMS, a User-Defined Type (UDT) allows:
Automatic data compression
Users to create custom data types beyond standard SQL types
Tables to store only primitive data types
Faster query execution
Which statement best differentiates RDBMS, OODBMS, and ORDBMS?
RDBMS handles only objects; OODBMS stores tables; ORDBMS is non-relational
RDBMS uses tables, OODBMS uses objects, ORDBMS blends both models
All three are purely hierarchical
ORDBMS removes SQL support entirely
Which model is best suited for web applications that use both structured and multimedia data?
RDBMS
OODBMS
ORDBMS
Hierarchical DBMS
