Question Bank

The ACID properties are a set of principles that ensure reliable processing of database transactions. They stand for Atomicity, Consistency, Isolation, and Durability. These properties guarantee that transactions are processed in a way that maintains the integrity of the database. ACID Properties: 1. Atomicity: Atomicity ensures that a transaction is treated as a single, indivisible … Read more

Serializability theory in transaction management is a concept that ensures even when multiple transactions are executed concurrently in a database, the final result will appear as if they were executed one after another in a sequential order, preventing data inconsistencies and maintaining a database integrity; essentially, it guarantees that the outcome of concurrent transactions is … Read more

Comparison Summary Mechanism Lock-Based Timestamp-Based Optimistic Concurrency Control Suitable for High contention, critical consistency, centralized lock management Distributed systems, read-dominant workloads, strict ordering Low contention, read-intensive workloads, high throughput How it works Uses locks to control access to data and ensure consistency Assigns timestamps to transactions to enforce serial order Transactions execute without restrictions and … Read more

Distributed query optimization algorithms play a crucial role in improving the performance of query processing in distributed database systems. They aim to minimize the cost of executing queries by determining the most efficient way to execute them, considering factors such as data distribution, network communication, and resource utilization. Key Goals of Distributed Query Optimization Algorithms: … Read more

A Distributed Database Management System (DDBMS) is software that manages a distributed database, ensuring data storage, retrieval, and updates across multiple locations while maintaining consistency and coordination. It provides users with a unified view of the database, handles transactions, and ensures data integrity, security, and fault tolerance in a distributed environment. In a Distributed Database … Read more

A distributed database is a database system where data is stored across multiple physical locations or servers, which may be in different geographical areas. These databases are interconnected through a network, allowing users to access and manage data as if it were stored in a single location. Distributed databases improve scalability, fault tolerance, and performance … Read more

1. Data Fragmentation and DistributionChallenge: Views often need to aggregate or join data from multiple fragments distributed acrossdifferent nodes.Impact: This increases query complexity and communication overhead, as data must be fetched frommultiple locations. 2. Consistency MaintenanceChallenge: Ensuring that views reflect the most up-to-date data from underlying base tables, especiallywhen data is updated at different nodes.Impact: … Read more

1. Autonomy in DDB Systems: Autonomy refers to the degree of independence each database site has interms of control over its own data, transaction management, and query execution. Types of Autonomy:i. Design Autonomy: Each site can define its schema and constraints independently.ii. Execution Autonomy: Each site can decide how to execute queries and transactions.iii. Communication … Read more

Fragmentation in Distributed Databases Fragmentation is the process of breaking a large database into smaller parts, called fragments, which are stored across different locations. These fragments ensure that data can be efficiently managed and accessed while maintaining the ability to rebuild the original database without losing any information. For example, if a table T is … Read more

A distributed database is a database that is not stored at a single location but is distributed across multiple physical sites or servers. These sites may be located in different geographical locations, and the data is partitioned or replicated across these locations. Each site or node in a distributed database system can independently process transactions, … Read more