ADVANTAGE AND DISADVANTAGE OF USING DATABASE SYSTEM.

Advantage and disadvantage of using database system

Describe the Advantage and disadvantage of using database system.

History Of Database

Data are raw facts that compose building blocks of information. Database is a group of information and a means to manipulate data in a useful way, which must provide proper storage for large amounts of data, easy and fast access and facilitate the processing of data. Database Management System (DBMS) is a set of software that is used to define, store, manipulate and control the data in a database.

From pre-stage flat-file system, to relational and object-relational systems, database technology has gone through several generations and its 40 years history.(Galindo,2008,213)

 In the 1960's, the use of main frame computers became widespread in many companies. To access vast amounts of stored information, these companies started to use computer programs like COBOL and FORTRAN.

Data accessibility and data sharing soon became an important feature because of the large amount of information required by different departments within certain companies. With this system, each application owns its own data files. The problems thus associated with this type of file processing were uncontrolled redundancy, inconsistent data, inflexibility, poor enforcement of standards, and low programmer maintenance.(Gray,2002,86)

 The Evolution of the Database

 Ancient History: Data are not stored on disk; programmer defines both logical data structure and physical structure, such as storage structure, access methods, I/O modes etc. One data set per program: high data redundancy. There is no persistence; Random access memory (RAM) is expensive and limited, programmer productivity low. (Galindo,2008,213)

1968 File-Based: predecessor of database, Data maintained in a flat file. Processing characteristics determined by common use of magnetic tape medium.

Data are stored in files with interface between programs and files. Mapping happens between logical files and physical file, one file corresponds to one or several programs

Various access methods exits, e.g., sequential, indexed, random

Requires extensive programming in third-generation language such as COBOL, BASIC.

Limitations:

Separation and isolation: Each program maintains its own set of data, users of one program may not aware of holding or blocking by other programs.

Duplication: Same data is held by different programs, thus, wastes space and resources.

High maintenance costs such as ensuing data consistency and controlling access

Sharing granularity is very coarse

Weak security

1968-1980 Era of non-relational database:

A database provides integrated and structured collection of stored operational data which can be used or shared by application systems. Prominent hierarchical database model was IBM's first DBMS called IMS. Prominent network database model was CODASYL DBTG model; IDMS was the most popular network DBMS.

Database in our life

The various columns or attributes in a database would then be modeled by the adjectives we might associated with the various items in each group hair color, attention span, classes attending for students type of ticket, location traveling from or to, items carried for passengers pay rate, length of service, location in building for employees color, distance from stamen, photosynthetic state for petalssize, weight, material for objects. (Galindo,2008,213)

Advantages

It means all of the information is ...