Advantages and Disadvantages of Distributed Databases over Centralized Databases / Relative Advantages of Distributed Databases / Disadvantages of Distributed Databases / Discuss the Advantages and Disadvantages of Distributed Databases / Advantages of Distributed Databases compared to Centralized Databases / Advantages and Disadvantages of Distributed Database Management System / Advantages and Disadvantages of Distributed Database System over Centralized Database System
Advantages of Distributed Database System
1. Increased reliability and availability – A distributed database system is robust to failure to some extent. Hence, it is reliable when compared to a Centralized database system.
2. Local control – The data is distributed in such a way that every portion of it is local to some sites [servers]. The site in which the portion of data is stored is the owner of the data.
3. Modular growth [resilient] – Growth is easier. We do not need to interrupt any of the functioning sites to introduce [add] a new site. Hence, the expansion of the whole system is easier. Removal of site is also does not cause much problems.
4. Lower communication costs [More Economical] – Data are distributed in such a way that they are available near to the location where they are needed more. This reduces the communication cost much more compared to a centralized system.
5. Faster response – Most of the data are local and in close proximity to where they are needed. Hence, the requests can be answered quickly compared to a centralized system.
6. Reflects the organizational structure – Normally, database is fragmented into various locations wherever we have controls.
7. Secured management of distributed data – Various transparencies like network transparency, fragmentation transparency, and replication transparency are implemented to hide the actual implementation details of the whole distributed system. In such way, Distributed database provides security for data.
8. Robust – The system is continued to work in case of failures. For example, replicated distributed database performs in spite of failure of other sites.
9. Complied with ACID properties – Distributed transactions demands Atomicity, Consistency, Isolation, and Reliability.
10. Improved performance and Parallelism in executing transactions can be achieved.
Disadvantages of Distributed Database Systems
1. Complex Software – Complex implementation. Costs more in terms of software cost compared to a centralized system. Additional software might be needed in most of the cases over a centralized system.
2. Increased Processing overhead – It costs many messages to be shared between sites to complete a distributed transaction.
3. Data integrity – Data integrity becomes complex. Too much network resources may be used.
4. Different data formats might be used – This may cost time.
5. Deadlock is difficult to handle compared to a centralized system.
6. May cause much more network traffic in case of write operation in a replicated form of distributed database.
7. Distributed System supported Operating System is required to implement distributed database system.
8. The data shared between sites over networks are vulnerable to attack. Hence, network oriented security protocols to be used based on the sensitivity of data shared.
9. More complex in terms database design – According to various applications, we may need to fragment a database, or replicate a database or both.
10. Handling failures is a difficult task. In some cases, we may not distinguish site failure, network partition, and link failure.Distributed databases basically provide us the advantages of distributed computing to the database management domain. Basically, we can define a Distributed database as a collection of multiple interrelated databases distributed over a computer network and a distributed database management system as a software system that basically manages a distributed database while making the distribution transparent to the user.
Distributed database management basically proposed for the various reason from organizational decentralization and economical processing to greater autonomy. Some of these advantages are as follows:
Distributed Database Systems is a kind of DBMS where databases are present at different locations and connected via a network. Each site in a Distributed Database is capable of accessing and processing local data as well as remote data. Although, distributed DBMS is capable of effective communication and data sharing still it suffers from various disadvantages are as following below.
- Complex nature :
Distributed Databases are a network of many computers present at different locations and they provide an outstanding level of performance, availability, and of course reliability. Therefore, the nature of Distributed DBMS is comparatively more complex than a centralized DBMS. Complex software is required for Distributed DBMS. Also, It ensures no data replication, which adds even more complexity in its nature.
- Overall Cost :
Various costs such as maintenance cost, procurement cost, hardware cost, network/communication costs, labor costs, etc, adds up to the overall cost and make it costlier than normal DBMS.
- Security issues:
In a Distributed Database, along with maintaining no data redundancy, the security of data as well as a network is a prime concern. A network can be easily attacked for data theft and misuse.
- Integrity Control:
In a vast Distributed database system, maintaining data consistency is important. All changes made to data at one site must be reflected on all the sites. The communication and processing cost is high in Distributed DBMS in order to enforce the integrity of data.
- Lacking Standards:
Although it provides effective communication and data sharing, still there are no standard rules and protocols to convert a centralized DBMS to a large Distributed DBMS. Lack of standards decreases the potential of Distributed DBMS. - Lack of Professional Support:
Due to a lack of adequate communication standards, it is not possible to link different equipment produced by different vendors into a smoothly functioning network. Thu several good resources may not be available to the users of the network. - Data design complex:
Designing a distributed database is more complex compared to a centralized database.
If the data is not properly distributed at different sites, then the query processing time will increase and response to requests will become slow.