There are many aspect that let us do a comparing between centralized and distributed DBMS:
Database direction system is any package that manages and controls the storage, the organisation, security, retrieval and built-in of informations in a specific database, whereas DDBMS consist of a individual database that is divided into many fragments. Each fragment is integrated on one or more computing machine and controlled by independent database ( DBMS ) ( Connolly & A ; Begg, 2004 ) .
In centralized DBMS the information is distributed across the web computing machines, and the information is stored on many sites and under the direction duty of DDBMS. But in the DBMS information is stored and controlled in a cardinal site.
Both of DDBMS and centralized DBMS provide the entree to database utilizing the same interface, but for this map centralized DBMS faces less complication than DDBMS.
For administering informations over web we can utilize reproduction or atomization. The aim of reproduction and atomization is to do a transparence of this allotment to do the inside informations of execution hidden on users. In centralised DBMS is non need to do transparences.
In DDBMS design we can happen three issues which are non in centralised DBMS design. These issues are: How to divide the database to fragments, and fragments to retroflex, and in which locate we can happen these fragments.
Consequently, centralised DBMS is less sophisticated than DDBMS because it non supports the organisational construction of today ‘s widely distributed endeavors, and DDBMS more reactive and dependable ( Blurtit, 2010 ) .
2- Advantages of DDBMSs
The DDBMS have many advantages over DBMS. We can garner them in the undermentioned points:
Reflects organisational construction: We can administer the informations base over any organisation offices which has distributed locations
Improved shareability and local liberty: Users can utilize the informations of other sites, which mean the informations can be near of the users who use it. Besides by this manner the informations can be controlled by the user.
Improved handiness: Unlike centralized DBMS, the failure at one site or nexus of communicating makes merely some parts of system unaccessible, which means the full system is still working.
Improved dependability: The reproduction system make the informations exist in many site. So this insures the possibility of accessing to this information if there is any failure happened.
Improved public presentation: We can better the accessing velocity to data base if we use distant centralised database. Besides, there may non be same struggle for CPU and utilizing the services, like DBMS.
Economicss: For doing the organisation systems more cost-efficient to obtain separate computing machines, DBMS allows us to make systems of smaller computing machine, its power equal the power of one big computing machine.
Modular growing: This one refers to the flexibleness of DDBMS, where we can add a new site without any affects on the operation of other sites.
Complexity: The characteristics of DDBMS like reproduction, handiness flexibleness make the execution of DDBMS more complex than centralized DBMS.
Cost: The cost will increase due to the complexness in DDBMS than centralized DBMS. It requires the care and extra hardware to make a web between the stations.
Security: Unlike centralised system, entree to data non merely has to be secured, but the full web besides has to be made secure.
Integrity control more hard: In a DDBMS, the costs of processing and communicating that we have to do to implement unity restraints may be prohibitory.
Lack of criterions: Despite there is effectual communicating when we use DDBMS, There are no methodological analysiss or tools to help users convert a centralised DBMS into a distributed DBMS.
Lack of experience: Unlike what we have with centralized DBMSs, still our experiences are lack in industry of DDBMS.
Database design more complex: The design of DDMBS is more complex than centralised database, because the information atomization has to be implemented in this design, and besides informations reproduction, and fragments allotment to specific sites
4- Possibility of utilizing the reproduction waiter:
The reproduction is a mechanism enables the companies to supply their users accessing to current informations at the clip they need it ( Connolly & A ; Begg, 2004 ) .
The DreamHome company can utilize the reproduction waiter to heighten the dealing with demands, because if it want to do any updates to a reproduction object at one site are will be applied to their transcripts at all other sites. Furthermore, reproduction waiter enables the company users to retroflex many objects, such as the tabular arraies and Functions and Procedures, Indexes, Views and Object Views, Packages and Package Bodies and so on ( Urbano, 2003 ) .
Execution of reproduction waiter can be utile. Because by it users can reassign informations to any local site needs it. And the company can see handiness of informations and applications at all the clip. Companies can see that of import applications are available at all times. Besides, reproduction waiter allows any user entree to its informations from distance ( DCI, 1996 ) . So that it is possible to utilize waiter of reproduction in this company.
Finally the recommendations that we can give this company are
It ‘s better to implement DDBM to pull off the information of this company.
If this company usage same operating system like Windows or Linux, it is better to incorporate Homogeneous DDBMS, because, Its design is easier than heterogenous DDBMS, every bit good as informations managing, besides It helps the company to add new sites to DDBMS. Equally good as It allows augmented public presentation by utilizing the parallel processing capableness of multiple sites ( Edward, 2007 ) .
Blurtit, d. ( 2010 ) . Ask it reply it. Retrieved April 11, 2010, from blurtit: hypertext transfer protocol: //www.blurtit.com/q828920.html
Connolly, T. M. , & A ; Begg, C. E. ( 2004 ) . Data base solution. A measure by measure guide to buildind database. England: Pearsoned.
DCI, D. ( 1996 ) . Reproduction, The Following Generation of Distributed Database Technology. Retrieved March 13, 2010, from DCI ‘s Event Central: hypertext transfer protocol: //www.dciexpo.com/geos/replica2.htm
Edward, C. ( 2007, Novamber 05 ) . Distributed DBMS Concepts and Design. Retrieved March 13, 2010, from SJSU Department of Computer Science: hypertext transfer protocol: //www.cs.sjsu.edu/~lee/cs157b/fall2003/Edward_Chen_Chapter % 2022.ppt.
Urbano, R. ( 2003 ) . Oracle Database Advanced Replication. Oracl.