Data Allocation in Distributed Database Design
there is a need for a well-maintained database to maintain its functionality. Earlier, databases used to be centralized in nature. But, with the boost in globalization, organizations inclined to diversify throughout the globe. These days, instead of opting for a central database, many organizations choose to distribute data over local servers. This distribution of data over various servers is generally known as distributed databases. A distributed database system is the collection of logically interrelated data, distributed across various locations that communicate via a computer network.
To ensure a successful database management system, it is vital to carefully work out a strategy to align the data requirements and business agenda of your organization. Hiring the services of a database development company can be of great help in creating and implementing database solutions. A professional company can help you in determining the best database management system and test database programs. Many database development companies these days provide custom database solutions provider inclined to client’s needs to help efficient management and security of crucial business data.
Since its introduction, Distributed database systems have eliminated many shortcomings of the centralized database systems and fit more in the decentralized structures of many organizations. Here are some of the key benefits of a distributed database system over the centralized database system, have a look:
- Reliability and Availability: Distributed database systems are more reliable as compared to a centralized database system. In the case of database failures, the whole system of centralized databases comes to an end. Whereas, in the case of distributed database systems, if a component fails, the performance of the system continues may be at a slower rate.
- Modular Development: In the case of centralized database systems, if the system requires to be extended to new locations or new units, the action needs substantial efforts and interruption in the existing functioning. But, in a distributed database system, the expansion work simply requires adding new computers and local data to the new site and finally connecting them to the distributed system without disturbing the existing functionality.
- Quick Response: When data is distributed in an efficient manner, the user requests or queries can be met from local data itself, thus offering a quick response. In the case of centralized database systems, all kinds of queries need to pass through the central computer for processing, which may lead to delay in response.
- Lower Communication Overhead: When data is positioned locally where it is frequently used, then the communication costs for data management can be minimized. However, in the case of centralized database systems, the communication costs are quite high.
- Secured Management of Distributed Data: A number of transparencies such as fragmented transparency, network transparency, and replication transparency are implemented to cover the actual implementation details of the entire distributed system. Thus, distributed database systems provide more security of data as compared to centralized database systems.
Allocation of Data in a Distributed Database
Regardless of offering so many benefits over centralized database systems, the allocation of data is one of the key design issues of a distributed database system. The techniques that are used for distributed database design can be categorized as:
- Fragmentation: Technique that is used to break up the database into logical units is known as fragmentation. Fragments can be assigned for storage at different sites. The fragmentation techniques can be further divided into vertical fragmentation, horizontal fragmentation, and hybrid fragmentation. Increased efficiency, local query optimization, security, and privacy are some of the main benefits of the fragmentation technique.
- Replication: Data replication technique permits certain data or copies of the database to be stored in more than one site. It is a well-admired fault tolerance technique of distributed databases. Moreover, reliability, quicker response, reduction in network load and simpler transactions are some of the key advantages of the data replication technique.
- Allocation: The allocation technique is used for the allocation of fragments or replicas of fragments for storage at various sites.
All the information concerning data fragmentation, allocation, and replication is stored in a global directory. This directory can be accessed by the DDBS applications as and when required.
Distributed Database System-Database Control
Database control is basically the task of enforcing regulations so as to provide accurate data to genuine users and applications of a database. This task is generally performed by a Database Administrator (DBA). To ensure that the correct data is being provided to users, all data should conform to the integrity constraints defined in the database. Apart from this, data needs to be protected from unauthorized users in order to maintain the security and privacy of the database. Thus, the key dimensions of database control are:
- Authentication: Authentication is the process in which only legitimate users can have access to the data resources. Authentication in a distributed database system can be enforced in two levels- a) controlling access to the client computer, where user access is restricted while login to the client computer that provides user-interface to the database server. B) Controlling access to the database software, where database software/administrator assigns some credentials to the user that can be used to gain access to the database.
- Access Rights: Access rights to a user generally refer to the privileges that the user is offered regarding DBMS operations. It may include the rights to create a table, drop a table, add, delete or update tuples in a table or query upon the table.
- Integrity Constraints: The integrity constraints are used to ensure the accuracy and consistency of the database system. The integrity constraints can be categorized as- data type integrity constraint, entry integrity constraint, and referential integrity constraint.