Assignment : 2 - abeerafatima/learning-database GitHub Wiki

what is centralized database?

                   A centralized database  is a database that is located, stored, and maintained in a single location. This location is most often a central computer or database system, for example a desktop or server CPU, or a mainframe computer.  In most cases, a centralized database would be used by an organization  or an institution.

ADVANTAGES :

  1. Data integrity is maximised and data redundancy is minimised.
  2. Data security. 3)Better data preservation than other types of databases due to often-included fault-tolerant setup. 4)Easier for use by the end-user due to the simplicity of having a single database design. 5)Generally easier data portability and database administration. 6)More cost effective than other types of database systems as labour, power supply and maintenance costs are all minimised. 7)Data kept in the same location is easier to be changed, re-organised, mirrored, or analysed. 8)All the information can be accessed at the same time from the same location. 9)Updates to any given set of data are immediately received by every end-user.

DISADVANTAGES :

1)Centralized databases are highly dependent on network connectivity. The slower the internet connection is, the longer the database access time needed will be. 2)Limited access by more than one person to the same set of data as there is only one copy of it and it is maintained in a single location. 3) This can lead to major decreases in the general efficiency of the system. 4)If there is no fault-tolerant setup and hardware failure occurs, all the data within the database will be lost. 5)Since there minimal to none data redundancy, if a set of data is unexpectedly lost it is very hard to retrieve it back, and in most cases it would have to be done manually.

What are the Advantages and Disadvantages of Distributed Database Management System?

Advantages: 1)Improved share ability and local autonomy. 2)Improved availability. 3)Improved Performance. 4)Economics. 5)Modular growth.

Disadvantages of DDBMS

1)Complexity.
2)Cost 3)Security 4)Integrity control more difficult 5)Lack of Standards 6)Lack of experience 7)Database design more complex