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WorksheetsInformation Management Prefinal Exam
Total questions: 40
Worksheet time: 30mins
What is a transaction in a DBMS?
A set of SQL commands
A logical group of database operations
A database schema
A file stored in the database
Which ACID property ensures that a transaction's changes are permanent?
Atomicity
Consistency
Isolation
Durability
What does the 'A' in ACID stand for?
Access
Atomicity
Association
Action
When does a transaction enter the committed state?
After a system failure
After changes are permanently saved to the database
During a read operation
When the system is idle
Which recovery technique uses a log to restore a database after a system failure?
Buffering and Caching
Shadow Paging
Log-based recovery
Concurrency Control
In a system using immediate update, what happens if a rollback is initiated during a transaction?
The database remains unchanged
The log is destroyed and changes are discarded
The old state of data is restored from the log
The system terminates all active transactions
What does the isolation property of ACID ensure in a multi-transaction environment?
Data integrity is maintained by reverting incomplete transactions
No changes are visible until a transaction is committed
Transactions can access and modify the same data simultaneously
Transactions must be executed in the order they are submitted
Which of the following best describes a partially committed transaction?
A transaction that has completed execution but not yet committed
A transaction that failed during execution
A transaction that is active and reading or writing data
A transaction that has been aborted
How does concurrency control prevent conflicts in a database?
By logging changes made during a transaction
By using locking mechanisms to restrict access to data
By buffering transactions for future execution
By applying checkpoints at regular intervals
In a DBMS, what is the main function of the buffer manager?
To manage concurrent access to the database
To log all database transactions
To store and transfer data between memory and disk
To schedule and prioritize transactions
Which ACID property ensures that a transaction transforms the database from one consistent state to another?
Isolation
Atomicity
Consistency
Durability
What would happen if the recovery mechanism in a DBMS failed to maintain atomicity during a system crash?
The database would become permanently inaccessible
Partially updated data would be visible, leading to inconsistencies
All transaction logs would be erased
Data recovery would require manual intervention
How does log-based recovery use checkpoints to ensure efficient recovery in case of a system failure?
By skipping uncommitted transactions and re-executing successful ones
By restoring the entire database from scratch using shadow paging
By restoring data starting from the last checkpoint to minimize recovery time
By removing failed transactions and archiving the logs
If a transaction fails during the committed state, which mechanism ensures the durability of the transaction?
Shadow paging
Immediate rollback
Transaction logging and recovery
Buffering and caching
In a timestamp-based concurrency control protocol, what happens when two conflicting transactions have the same timestamp?
Both transactions are aborted
The system assigns a new timestamp to both transactions
The transaction with the older timestamp is given priority
Both transactions are serialized and executed simultaneously
What is a distributed database?
A single database file located in one site
A database spread across multiple physical locations
A database stored only in cloud environments
A database accessible from a single computer
Which of the following is true about a centralized database?
Data is distributed across multiple locations
It involves multiple databases connected via a network
It is a single database file located at one site
It synchronizes data across all nodes
What does the two-phase commit (2PC) operation ensure in a distributed transaction?
It splits data into partitions for better access
All operations are completed successfully, or none are
Data is copied and stored across multiple nodes
The database is horizontally scalable
What feature of distributed storage allows data to be copied and stored across multiple nodes?
Partitioning
Replication
Query processing
Elastic scalability
What is one advantage of using a distributed storage system over a centralized one?
Lower redundancy
Improved scalability and cost efficiency
Higher latency in accessing data
Single-point failure prevention
Which type of distributed storage system wraps data into unique objects for storage and retrieval?
Block storage
Distributed file system
Object storage
Network-attached storage
In a distributed database, how is query processing optimized?
By performing all operations at a single node
By distributing tasks across the nodes for efficient execution
By limiting the number of queries processed at one time
By using only homogeneous DBMS products
What is the main role of a centralized DDBMS?
Ensures data replication across all nodes
Integrates distributed data logically as if stored in one location
Stores data in the cloud for better access
Manages multiple databases connected via a single server
How does fault tolerance benefit a distributed storage system?
It decreases system complexity
It allows data to remain accessible even during node failures
It reduces storage costs by minimizing redundancy
It synchronizes data between servers in real time
In a shared-disk architecture, what does each processor have access to besides the shared disk?
Its own local memory system
Another processor's resources
A backup server
Only shared network storage
What is one key benefit of partitioning in distributed storage systems?
Faster data replication across nodes
Simplified query execution on individual nodes
Fault tolerance through multiple copies of data
Reducing latency by placing data closer to its users
How would you design a homogeneous distributed database for a new organization seeking high scalability and performance?
Use different DBMS products for incremental growth
Implement the same DBMS software across all sites for parallel processing
Deploy multiple cloud systems with various DBMS models
Use heterogeneous DBMS systems for seamless integration
In a heterogeneous distributed system, how do gateways function to improve system efficiency?
By partitioning the data into blocks for faster access
By converting the language and model of different DBMS into a relational system
By allowing homogeneous systems to replicate data seamlessly
By ensuring all queries are processed locally before distributed
How would you resolve the issue of data translation between different DBMS products in a heterogeneous distributed system?
By using a shared-nothing architecture to separate processing tasks
By translating data structures and query languages between systems
By storing all data in one node and replicating it later
By avoiding the use of multiple DBMS products
Which of the following best describes a shared-nothing system architecture in a parallel DBMS?
Processors share memory but not disks
Each processor uses its own disk and memory, communicating over a network
All processors access the same disk through a shared channel
Processors share all resources, including memory and storage
Which of the following best describes atomicity in a transaction?
All parts of a transaction must succeed or none at all
Transactions are executed one at a time
Data remains consistent after a crash
Changes are stored permanently
In a DBMS, what is the role of a transaction log?
To store frequently accessed queries
To maintain a history of all changes for recovery
To manage memory allocation
To improve data replication speed
Which concurrency control method allows multiple transactions but ensures serializability?
Locking protocol
Shadow paging
Buffer management
Query optimization
What is the main purpose of checkpointing in recovery management?
To reduce the size of the transaction log
To guarantee durability of transactions
To mark a safe state for restarting recovery
To terminate unfinished transactions
Which of the following is NOT an advantage of distributed databases?
Improved reliability
Lower communication overhead
Local autonomy
Scalability
What is the difference between replication and partitioning in distributed databases?
Replication splits data across sites, partitioning duplicates data
Replication duplicates data across sites, partitioning divides data into subsets
Replication is used for indexing, partitioning for storage
Both replication and partitioning mean the same thing
Which component of DBMS is responsible for managing concurrency control?
Recovery Manager
Buffer Manager
Transaction Manager
File Manager
What does consistency in ACID ensure?
The database will not allow duplicate data
The database remains valid before and after a transaction
The transaction completes without interruption
The database operations are executed in order
In a distributed database, what is data fragmentation?
Copying data across multiple servers
Breaking a database into smaller logical pieces stored at different sites
Storing redundant data for backup purposes
Compressing large data into smaller blocks
Which recovery technique avoids cascading rollbacks?
Deferred update
Immediate update
Shadow paging
Two-phase commit
