components of DDBMS
DDBMS (Distributed Database Management System) consists of various components that work together to support the management and processing of distributed databases. These components include:
1. Distributed Database: It is the core component of a DDBMS, which consists of multiple database fragments that are distributed across different nodes or sites in a network. Each fragment can be a subset of a larger database or a complete database.
2. Distributed Data Dictionary: It stores the metadata related to the distributed database, including the schema information, data definitions, access controls, and relationships between different database fragments. It helps in maintaining consistency and integrity across the distributed database system.
3. Distributed Query Processing: This component is responsible for processing queries that span multiple database fragments distributed across different sites. It includes query optimization, query decomposition, and query execution across multiple sites to retrieve the required data.
4. Distributed Transaction Management: It manages the execution of distributed transactions that involve accessing and updating data in multiple database fragments distributed across different sites. It ensures the ACID properties (Atomicity, Consistency, Isolation, Durability) of distributed transactions and handles concurrency control and transaction recovery.
5. Data Replication and Fragmentation: DDBMS allows data replication and fragmentation to enhance the availability, performance, and fault tolerance of the distributed database. Data replication involves maintaining multiple copies of data at different sites, while data fragmentation involves dividing the data into smaller fragments and distributing them across sites based on certain criteria.
6. Distributed Concurrency Control: It is responsible for managing concurrent access and updates to the data items in a distributed database. It ensures that multiple transactions executing concurrently on different database fragments do not interfere with each other and maintains data consistency.
7. Distributed Security and Authentication: This component ensures the security and privacy of data in a distributed database. It includes access control mechanisms, encryption, authentication, and authorization methods to protect the data from unauthorized access and ensure data integrity.
8. Distributed Deadlock Detection: It is responsible for detecting and resolving deadlocks that can occur in a distributed database environment due to concurrent execution of transactions. It uses various algorithms and techniques to identify and break deadlocks to ensure the smooth execution of transactions.
9. Distributed Backup and Recovery: It provides mechanisms for creating backups of data and recovering the database in the event of failures or disasters. It includes features like incremental backups, point-in-time recovery, and distributed disaster recovery planning to ensure data availability and reliability.
10. Distributed Monitoring and Administration: This component includes tools and utilities to monitor the performance, availability, and resource usage of the distributed database system. It also facilitates administrative tasks such as database configuration, performance tuning, and system monitoring to ensure efficient management of the distributed database.