https://drive.google.com/file/d/1qyJZ1vQVKWi1cXAd6GKgkMyadIDHxV4Q/view?usp=sharing
A distributed database system (DDBS) stores and manages data across multiple interconnected computers or sites, offering advantages such as higher availability, reliability, and better performance compared to centralized systems. The overall data appears as a single logical database to the users. Distributed Database Management Systems (DDBMS) can have various architectural models, including client-server, peer-to-peer, and federated, and can be classified as homogeneous or heterogeneous based on site identity, operating system, and data structure. Distributed database design involves fragmentation (splitting data into smaller parts) and allocation (placing fragments at different sites), which can involve replication (storing copies of data). Query processing in a DDBS involves transforming a high-level query into an efficient execution plan, optimizing for total cost and response time, incorporating steps like decomposition, data localization, and global query optimization. Transaction management ensures the ACID properties, with concurrency control mechanisms like locking and timestamp ordering managing simultaneous access to maintain database consistency.
Here are 5 key bullet points of the specific topics covered with a brief definition for each:
Here are 5 key bullet points of the specific topics covered with a brief definition for each:
- Distributed Database System (DDBS): A database system that stores data across multiple computers or sites connected by a network, where each site has its own database, forming a single, integrated system.
- Fragmentation: The process of dividing a table (relation) into a set of smaller tables (fragments) to be stored on different sites, a technique used in distributed database storage.
- Distributed Query Processing: The procedure of answering queries on data stored at multiple sites in a computer network, involving the translation of a high-level query into an efficient execution plan.
- Transaction Management: Deals with transactions, which are sets of operations that perform a single logical unit of work, ensuring ACID properties like atomicity, consistency, isolation, and durability.
- Concurrency Control: Mechanisms (e.g., locking, timestamp ordering) used in a distributed DBMS to synchronize access to the database by multiple concurrent users, ensuring database consistency and isolation.
This PDF explores concepts related to Distributed Database Management Systems (DDBMS), Object-Oriented Programming (OOP), and Distributed Object Design. It begins by outlining the four fundamental principles of OOP: encapsulation, abstraction, inheritance, and polymorphism, providing simple explanations and examples for each.
The document then transitions to DDBMS, focusing on concurrency control. It details the use of Two-Phase Locking (2PL) and models for centralized, primary copy, distributed, and voting 2PL in DDBMS with data replication. Furthermore, the document discusses DDBMS architecture, including transparencies (data, network, replication, fragmentation) and the ANSI/SPARC model. It covers data organizational views like fragmentation and replication, and the allocation problem. Finally, it touches upon distributed object storage, comparing Block & File with Object storage, and object query processing, emphasizing minimizing total cost and response time.
5 Key Bullet Points of Specific Topics:
The document then transitions to DDBMS, focusing on concurrency control. It details the use of Two-Phase Locking (2PL) and models for centralized, primary copy, distributed, and voting 2PL in DDBMS with data replication. Furthermore, the document discusses DDBMS architecture, including transparencies (data, network, replication, fragmentation) and the ANSI/SPARC model. It covers data organizational views like fragmentation and replication, and the allocation problem. Finally, it touches upon distributed object storage, comparing Block & File with Object storage, and object query processing, emphasizing minimizing total cost and response time.
5 Key Bullet Points of Specific Topics:
- Encapsulation: The principle in OOP where an object keeps its state private, inside a class, and other objects can only interact with it through a list of public functions called methods.
- Two-Phase Locking (2PL): A concurrency control method for transactions in DDBMS where data elements are locked before they are accessed, and locks are released only after the transactions commit or abort. Types discussed include centralized, primary copy, distributed, and voting 2PL.
- Network Transparency: A form of transparency in DDBMS, also known as distribution transparency, where an operation on data is independent of both the location and the system where it is executed.
- Fragmentation: The decomposition of relations in a database, which is used for partitioning to improve locality, avoid unnecessary replication, and allow concurrent transaction execution.
- Object Storage: A storage approach where data is stored as individual objects, each consisting of an object identifier (OID), the data, and metadata, using a flat organization scheme for greater scalability.
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