What you should know about a Database

A database is a data bank, archive, or catalogue.  It is a collection of records.  A database is a systematically arranged collection of computer data structured so that it can be automatically retrieved or manipulated.

APPLICATION SPECIFIC FILES VERSUS DATABASE

File processing systems were used before the advent of database management systems. 

File processing systems had problems of data redundancy and data inconsistence.  In an organization, each department has its own file in the file processing system.  This allows same fields to be stored in multiple files. This leads to waste of resources and time.

When a new member is added or recruited by an organization, it will require the effort of the management to enter the details into different files to balance the record. It also requires the same process when a worker is retired or retrenched.

Data redundancy also increases the possibility of errors.  When an employee changes a residence address, it requires personnel in different levels of management to update the address.  This has to be done on different computers across the organization. There is a high tendency of forgetting to update the address if one of the secretaries is not on seat.  This can lead to discrepancies when the record is not updated accordingly.

Issues of data inconsistence arise in use of file processing systems.  A college has a file containing admission list, departmental list and faculty list.  Whenever new sets of students are admitted into the college, their data has to be entered into all the files.  In cases where the students are much, there is a high tendency of missing out some names.  When the admission secretary also forgets to enter the details into the other files it leads to data inconsistence.  This can lead to controversial issues in the college.  Some students could be disqualified from writing exams in future because of missing records.

A database system was designed to address these flaws and checkmate issues of data redundancy and inconsistence.  The use of a database system allows many programs and departments of an organization to share data in the database.  The manipulation of data reflects directly in a general database instead of a specific file.  This ensures reduced data redundancy.

Inconsistence is avoided since redundancy is reduced.  When information of newly admitted students is entered at the departmental level, it reflects in the faculty, bursary and student affairs department.  This is because a central database is used across the organization.

Database systems allow data sharing.  The information of both employees and students can be accessed from any computer in the organization. The level of information accessible is dependent on the privileges given by the database administrator.

Database systems encourage enforcement of standards. The centralized data control system ensures that standards are maintained in stored data formats.  This is useful for data interchange or data migration between two or more systems.

Database systems have security restrictions. This system ensures that only authorized personnel have access to the database.  The database administered defines security checks to be carried out at different levels to prevent unauthorized access.

Database systems ensure data integrity.  This is due to the high level of security implemented and the database approach.

The system also reduces the time the management of an organization use to carry out their operation.  It reduces the work of human machineries since the database is programmed to do a lot of jobs at the same time.

The database system is the most used in organization today.  The file processing system has gradually been faced off because of its numerous setbacks.

DATABASE SYSTEMS (DBMS)

A database management system is a set of software programs that controls the systematic organization, storage, management and retrieval of data in a database.  The database management system allows different user application program to concurrently access the database.  The DBMS use database models like relational model and object model to describe and support application.  The DBMS support query languages which are high level programming languages.

A database management system provides facilities for controlling data access, enforcing data integrity, managing concurrency control, maintaining database security and restoring database after failures.

A DBMS works with database servers which are dedicated computers.  These computers hold the actual databases and run only the DBMS and related software.  The servers are usually multiprocessor computers with generous memories and redundant array of independent disks used for stable storage.

The components of a database include a DBMS engine, data definition subsystem, data manipulation subsystem, application generous system and database administration subsystem.

The DBMS engine accepts logical requests from various other DBMS subsystems.  It converts them into physical equivalents and access the database and dictionary as they exist on a storage device.

The data definition subsystem helps the user to create and maintain the data dictionary.  It also defines the structure of the files in the database.

The data manipulation system helps a user to add, change and delete information in a database and query it for valuable information.  The software tools used within the data manipulation system are mostly primary interfaces between a user and the information in a database.

The application generation subsystem contains facilities that help users develop transaction intensive applications.  It facilitates easy to use data entry screens, programming languages and interfaces. 

The data administration subsystem helps users to manage the overall database environment by providing facilities for backup & recovery, security management, query optimization, concurrency control and change management.

The architecture of a database management system is divided into external, conceptual and internal level.

The external level is called the user view.  It is the highest level.  It is the level closer to the user.  This view describes only a part of the actual database.  Only the part relevant to the user is visible.

End users and application programmers get different external views.  A cashier and a database administrator will get different views of the database.  These users use a language to carry out the database operations.  The application programmer uses conventional third-generation languages like COBOL or C.  They also use fourth generation languages specific to the database like visual FoxPro or Microsoft access.  The end user uses a query language to access data in a database.  This query language is a combination of data definition language (DDL), data manipulation language (DML) and data control language (DCL).  The data definition language defines and declares the database objects.  The data manipulation language performs operations on these objects.  The data control language controls the user access to the database objects.

The conceptual level comes between the external and internal levels.  It represents the entire database as a whole and is used by the database administrator.  This level is the view of data as it really is.  The data viewed at the external level is constrained by the language that is being used.  The conceptual level shows the data without any constraints.

The internal level deals with the physical storage of data.  It is the lowest level of architecture.  This level describes the physical sequence of the data stored.

All these levels of database architecture are connected by mappings.

A database management system has three functional components that manage the database; the database manager, the file manager and the disk manager.

DATABASE SOFTWARE PACKAGES

There are two categories of database software packages.  Some are used in small organizations while others are use in large organizations. Database software used in small organizations include Microsoft access, open office base and visual fox pro.

Microsoft access is a database tool used for gathering and understanding information used by an individual or small organization.  This information includes phone numbers, guest list, inventory items and other relevant data.  The software provides a convenient way to enter, navigate and report processed data.  It helps individual to monitor budgets and expenses over time.

Open office base is desktop DBMS software designed to meet the needs of different users.  It is used for processes like tracking compact disk collection and producing monthly departmental sales report.

The base software has wizards that help users to create tables, queries, forms, and reports.  It has a set of predefined table definitions for tracking customers, sales, orders, assets and invoices. The software delivers native support drivers for a variety of multi-user database engines like structural query language and Microsoft access.

The visual fox pro is a data centric object oriented and procedural programming language produced by Microsoft.  The software work in a variety of operating system environment like Macintosh, windows and Unix.  Visual fox pro is tightly integrated with its own relational database engine which extends its capabilities to support data manipulation.  It is a dynamic programming language that can be used to write middle ware and web applications.

Other database software used in larger organization include Microsoft SQL server, Oracle and My SQL.  Microsoft SQL server is a relational database server.  It is used for storing and retrieving data as requested by other software applications, either on the same computer or networked computers.  It is able to serve millions of users.  It also allows access to huge amount of data at the same time.  This software works with other hardware and is used by large organizations.

The oracle database is an object relational database management system.   It is produced and marketed by Oracle Corporation.  It’s database refer to defined groups of object ownership, such as schemes.  It is used in large organization across different management levels for management of data.  It is used in commercial and financial industries to reduce the work load of human resources.

My SQL is also my sequel structural query language.  It is a relational database management system that runs as a server.  It provides multi user access to a number of databases at the same time.  This software is used mainly for web application development.  It is used by large organizations to manage large amount of data.  Examples are face book and twitter.

These database softwares are used around the globe by individuals and organizations to program, manage and configure databases.