Open Source Database Open Source Database Management Software Management Software

available on the Netavailable on the Net

Umesha NaikUmesha Naik

andand

Prof. D ShivalingaiahProf. D ShivalingaiahDepartment of Studies in Library and Information

Science, Mangalore University, Mangalore -574 199, Karnataka, India

umeshai@yahoo.com d_shivaling@yahoo.com

IntroductionIntroductionOnline databases are organized collections of computerized information or data such as periodical articles, books, graphics and multimedia that can be searched to retrieve information. Databases can be general or subject oriented with bibliographic citations, abstracts, and or full text. Online databases that are retrieved on the World Wide Web are generally non-fee based, lack in-depth indexing, and do not index proprietary resources.

IntroductionIntroduction

Databases are programs that store information that needs to be accessed and reproduced in many different ways. Database is a structured collection of records or data that is stored in a computer system. The structure is achieved by organizing the data according to a database model. The model in most common use today is the relational model. Other models such as the hierarchical model and the network model use a more explicit representation of relationships.

Database Management System Database Management System (DBMS)(DBMS)

A DBMS is a set of software programs that controls the organization, storage, management, and retrieval of data in a database. DBMS are categorized according to their data structures or types. It is a set of prewritten programs that are used to store, update and retrieve a Database. The DBMS accepts requests for data from the application program and instructs the operating system to transfer the appropriate data. When a DBMS is used, information systems can be changed much more easily as the organization's information requirements change. New categories of data can be added to the database without disruption to the existing system.

History of Database Systems • 1940's, 50's Initial use of computers as

calculators. Limited data focus on algorithms. Science, military applications

• 1960's Business uses. Organizational data, customer data, sales, inventory, accounting, etc. File system based, high emphasis on applications programs to extract and assimilate data. Larger amounts of data, relatively simple calculations

• 1970's The relational model. Data separated into individual tables. Related by keys. Initially required heavy system resources. Examples: Oracle, Sybase, Informix, IBM DB2

History of Database Systems • 1980's Microcomputers - the IBM PC, Apple

Macintosh. Database program such as DBase, Paradox, FoxPro, MS Access. Individual user can create, maintain small databases

• Late- 1980's Local area networks. Workgroups sharing resources such as files, printers, e-mail

• Client/Server Database resides on a central server, applications programs run on client PCs attached to the server over a LAN

• 1990's Internet and World Wide Web make databases of all kinds available from a single type of client - the Web Browser

Structure of databasesStructure of databases • Understanding the structure of a database will

help you locate and retrieve information more efficiently.

• The information about each item in a database is called a record. For example, the Library Catalog has a record for each item (each book, journal, newspaper, video, map, etc.) located in the library. 

• A record is composed of individual elements of information called fields. All the records in a given database are composed of a common set of fields. These fields can be used as access points when searching a database.

Types of databases • Bibliographic databases - provide citations

(a listing of information about the item), and sometimes include abstracts (summaries) or descriptions of the items.

• Full-text databases - contain the full text of a work. 

• Numeric databases - provide mostly numeric data (numbers)  such as statistics or financial data.

Types of databases • Image databases - could include art prints,

photos, animations, and other types of images

• Audio/Video databases - could include audio clips of sound effects and music samples or video excerpts from speeches, television shows, or other broadcast media. 

• Mixed databases - combine two or more of the other database types.

Evolution of the database technology During the past three decades, the database technology for information systems has undergone four generations of evolution. The transition from one generation to the next has always been necessitated by the ever-increasing complexity of database applications and the cost of implementing, maintaining, and extending these applications. The first generation was file system, such as ISAM and VSAM. The second generation was hierarchical database systems, such as IMS and System 2000. The third generation was CODASYL database systems, such as IDS, TOTAL, ADABAS, IDMS, etc.

RDBMSA RDBMS is a DBMS that is based on the relational model as introduced by E. F. Codd. A RDBMS may be a DBMS in which data is stored in the form of tables and the relationship among the data is also stored in the form of tables. Relational Database is a database that groups of data using common attributes found in the data set. The resulting "clumps" of organized data are much easier for people to understand. The software used to do this grouping is called a RDBMS. The term "relational database" often refers to this type of software.

RDBMSDBMS is computer software that manages databases. DBMS may use any of a variety of database models, such as the network model or relational model. In large systems, a DBMS allows users and other software to store and retrieve data in a structured way. A DBMS is a computer program (or more typically, a suite of them) designed to manage a database, a large set of structured data, and run operations on the data requested by numerous users.

Web Database A web database is a data store or information repository that can be accessed via a query language or on application program. Unlike conventional database systems a web database access is not typically performed using queries typed at a command line or through custom designed programming interfaces. Web databases are accessed via other Web applications; especially forms that are developed using standardized HTML tags. HTML form interfaces enable is to create applications that integrate database functionality and provide access to organizational data repositories on behalf of Web clients.

Web Database A web database is designed for:

•better management of large document-based information repositories to internal and/or external users of the information.

•better use of legacy database systems, the information they contain, and existing applications.

Web Database •unlocking the potential of unused information held within organizational databases.  Information from databases within various parts of an organization, such as information relating to finance, human resources, project management etc, can be consolidated using Web-based applications and served to users as though it is available from a single source. 

•extending the functionality of the Web server so that the information is made available to internal and external users

The three-tier architecture model of a web database application

ConclusionAdvancement of Web technologies over the last decade has moved the database technology from close doors to outdoors.  Presently most of the websites require some basic level support at the backend through the databases. This process is also known as publishing database content through a Web server. The most basic feature a DBMS has is the underlying data schema.

ConclusionThis paper discusses the advantages of open source DBMS software and its availability, use, features, supporting interfaces, type of software. It is suggested that a database website offers many advantages over one built from static HTML pages. These include a consistency of style and content, the ability to present different views of the same data, devolved editing and enhanced security.