Distributed DBMS Part 1

assalamualaikum and hi everyone we are now in lecture 8 distributed database management systems dd BMS part 1 at the end of this lesson you should be able to describe distributed database TDB D DBMS distribute the processing share this share memory and share nothing of parallel DBMS and explain the advantages and disadvantages of D DBMS in a normal database or DBMS approach there will be a lot of systems and users who will access the same database at the same time the database approach is an improvement on the shared file solution as the use of a database management system DBMS provides facilities for querying data security and integrity and allow simultaneous access to data by number of different users in DBMS approach database is located at the server processing is split between server and client and less data traffic on the network usually a company might have multiple branches all over the places in running their business they may use centralized database to manage the operations in all of the branches centralized database system is commonly used in the organizations such as banks school and colleges to manage all the data in an appropriate manner by definition centralized database is a database system which resides at one of the nodes of a network of computers only one single location holds the database that can easily be accessed from any location by using internet connection such as one and LAN even though is still being used centralized database has so many problems the first one is performance degradation as number of remote sites group size grew means more user performance of database might be degraded because of that the second one is high cost to maintain large centralized databases that one is reliability problems with one central site loss of users you might not be able to access the database at Piccolo's the site with an database can become bottleneck the site's network might be congested by too many requests from users data availability is not efficient you need to wait if the data is being used by another user another possible availability problem is if the site with the database goes down there can be no data access hence to overcome the problem of centralized DBMS dd BMS is introduced instead of having one database at one centralized site the database is being fermented into few parts and being located at few sites distributed database is a logically interrelated collection of share data and a description of this data physically distributed over a computer network distributed DBMS or D DBMS is a software system that permits the management of the distributed database and makes the distribution transparent to user this is the concept of D DBMS the first one is it is a collection of logically related data the second one data split into fragments the fragments may be replicated and the fragments or the replicas allocated to sites the sites are linked by a communication network data at each site is under control of a DBMS and each DBMS participates in at least one global application parallel DBMS is a different method from D DBMS it is defined as a DBMS running across multiple processors and this that is designed to execute operations in parallel whenever possible in order to improve performance there are three main architecture for parallel DBMS the first one is share memory it is a tightly coupled architecture in which multiple processors within a single system share system memory the second one is shared this it is a loosely coupled architecture optimized for applications they are inherently centralized and require high availability and performance and if that one is said nothing often known as massively parallel processing MPP is a multiple processor architecture in which each processor is part of a complete system with its own memory and disk storage let's tackle on advantages of D DBMS the first one is reflects organizational structure many organizations are naturally distributed over several locations the company headquarters may wish to make global inquiries involving the access of data at all or number of a branch second it can improve share ability and local autonomy the geographical distribution of an organization can be reflected in the distribution of the data users at one site can access data stored at other sites data can be placed at the site close to the users who normally use the data next improve availability in a centralized DBMS a computer failure terminates the operations of the DBMS however a failure at one side of a DBMS or a failure of communication link making some size inaccessible does not make the entire system inoperable improve reliability as data may be replicated so that it exists at more than one side the failure of a node or a communication link does not necessarily make the data in accessible improve performance as the data is located near the site of greatest demand and given the inherent parallelism of distributed dbmss speed of database access may be better than the achievable from remote centralized database next is economics it is now generally accepted that it costs much less to create a system or smaller computers with the equivalent power of a single large computer moderner growth in a distributed environment it is much easier to handle expansion new sites can be added to the network without affecting the operation of other sites this flexibility allows an organization to expand relatively easily next is integration it is important for organizations to be able to integrate software components from different vendors to meet their specific requirements the last one is remaining competitive a lot of letter systems are using the DBMS concept hence to stay relevant company needs to follow the current train of the business let's take a look on these advantages of D DBMS the first one is complexity ad DBMS that hides the distributed nature from the user and provides an acceptable level of performance reliability and availability is inherently more complex than a centralized DBMS the fact that data can be replicated also as an extra level of complexity to the DBMS if the software does not handle data replication adequately there will be degradation in availability reliability and performance compared with a centralized system the second one is cause increased complexity means that we can expect the procurement and maintenance costs for a D DBMS to be higher than those for a centralized DBMS next is security in a centralized system access to the data can be easily controlled however in a distributed DBMS not only does access to replicate data have to be controlled in multiple locations but the network itself has to be made secure integrity control more difficult database integrity refers to the validity and consistency of store data integrity is usually expressed in terms of constraints which are consistency rules that the database is not permitted to violate and forcing integrity constraints generally requires access to a large amount of data that defines the constraint but which is not involved in the actual update operation itself in a DBMS the communication and processing cost they are required to enforce integrity constraints may be prohibitive next is lack of standard this lack of standards has significantly limited the potential of the DBMS there are also no tools or methodologies to help users convert essential as DBMS into a DBMS lack of experience general-purpose ddb MSS have not been widely accepted although many of the protocols and problems are well understood the last one is database design more complex besides the normal difficulties of designing a centralized database the design of a distributed database has to take account of fragmentation of data allocation of fragments to specific sites and data replications so I guess that's all for now see you again in the next part thank you

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Keywords: distributed database, distributed database management systems, ddb, ddbms, parallel dbms

Id: 8ZZ2eVuv2TI

Length: 10min 8sec (608 seconds)

Published: Mon Jun 08 2020