Introducing to Database and Database Management System

Concept of Data

In today’s world, it is said that information is power. Due to the rapid change of information technology, we have realized that the value of information, as a source. The importance of the speed and ease of which this resource can be managed is equally important to us. The term database literally means it is the basis of data.

Data can be defined as a set of isolated and unrelated raw facts, represented by values which have little meaning. Data are raw facts. The word 'raw' is used to indicate that the facts have not yet been processed to reveal their meaning. Data are information to the computer that is to be processed to get a relevant result. Processed results are called information.

Data has some key points to understand. These key points of data are:

1. Data constitute the building blocks of information.
2. Information is produced by processing data.
3. Information is used to reveal the meaning of data.
4. Good relevant and timely information are the key to good decision making.
5. Good decision making is the key to organizational survival in a global environment.

It is clear that timely and useful information requires good data. Such data must be generated properly and stored properly in a format that is easy to access and process. Data management is a discipline that focuses on the proper generation, storage and retrieval of data.

Data management is the core activity for any business, government organization, service organization or charity. Efficient data management requires the use of computer database. Information can be defined as a set of organized and validated collection of data. Knowledge is the act of understanding the context in which the information is used. It can be based on learning through information, experience, guessing intuition, etc. Based on the knowledge, information can be used in a particular text.

Thus, the term data processing means the process of collecting all items of data together to produce meaningful information. It can be done either manually or by the use of computers. If data processing is done with the help of computers, it is known as EDP (Electronic Data Processing).

Hence, the information that we obtain after processing the data must possess the following characteristics.

1. It must be accurate.
2. It must be available in time as required.
3. It must be complete so that more inference can be drawn.
4. It should be precise in meaning.
5. It should be relevant to the context.

Database

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A database is an organized collection of data in an easily accessible form which is shared and used for multiple purposes. In our day to day life, we come across several databases.

• In our home, we take care of our personal business with some database of a cheque book, phone book, address book, etc.
• In our offices, we keep information about our clients, their phone numbers, etc.
• We keep detailed information of our employees, their salary, their job description, etc.
• In school, we keep the records of students, their name, address, parents’ name, etc.
• Government agencies keep the records of the census.

A database contains records and fields. A record is a collection of different types of information about the same subject. In the case of the telephone book, the category address is a field.

In broader sense, a database is shared, integrated computer structure that houses a collection of:

1. End user data i.e. raw facts of interest to the end user.
2. Metadata or data about data through which the data are integrated.

Database Name: EMPLOYEE

Functions of Database

In a general file processing system, records are stored permanently in various files. There are numerous application programs which can extract records and add the records to the appropriate files. These processes have many advantages and disadvantages. They cannot provide data redundancy (duplication of data) and other facilities.

The functions of database are:

1. To store, manipulate and manage the information.
2. To reduce the repeated storage of the data (data redundancy) and improve the disk optimization.
3. To keep latest and correct information (Data Consistency).
4. To automate the data managing and processing system.
5. To provide data validation facilities.
6. To improve data security system.

Fundamentals of Database

Let ustake the example of the following table of some students. This reflects the database concept that based on data processing systems.

The above table contains cells. Each cell comprises of the outer border. The border thus formed has made a grid of cells. The combination of these cells is called Table.

Table: The database in Relational Database Management System (RDBMS) like MS-Access is in table form. There are many tables that you can create in a database. Each table has at least a primary key. The relation between these tables can be established with the following concept.

1. One to one: Relation between two primary keys of the two tables.
2. One to many: Relation between primary key and non-primary key of the two related tables.
3. Many to many: A link table between two tables can create many to many relations with the help of primary key and non-primary keys.

Field: A field is a piece of information about an element. A field is represented by a column. Every field has got a title called the field title.

Record: A record is an information about an element such as a person, student, an employee, client, etc. A record can have much information in different heading or titles.

Basic Terms of Database

Some important database-related terms are as follows:

• Data Type: A data type determines the type of data that can be stored in a column (field). The most common data types used in databases are Alphanumeric, Boolean and Data and time.

• Key: A key or key field is a column value in the table that is used to either uniquely identify a row of data in a table or establish a relationship with another table. The keys can be of three types. They are Primary key, Foreign key and Candidate key.

• Data Dictionary: The data dictionary defines the basic organization of a database. It contains the list of all files in the database, the number of records in each file and the names and types of each field.

Database Management System (DBMS)

Database Management System is a software that manages the data stored in a database. This is a collection of software which is used to store data, records, process them and obtain desired information. Since, data are very important to the end users, we must have a good way of managing data.

The DBMS contains a query language that makes it possible to produce a quick answer to ad-hoc queries. A query is a question and an ad-hoc query is a spur of the moment question.

The DBMS helps create an environment in which end users have better access to more and better-managed data than they did before the DBMS become the data management standard. Such access makes it possible for end users to respond quickly to the changes in their environment.

A DBMS is a collection of programs that manages the database structure and controls access to the data stored in the database. The DBMS make it possible to share the data in the database among multiple applications or users. The DBMS stands between the database and the user.

Features of Traditional Database System:

The most common database management systems used in early time were DB2, DBASEIII, DBASEIII+, FOXPRO, etc. The applications were developed independently for different departments and organizations and files of information relevant to one particular department were created and processed by dozens or even hundreds of separate programs.

The features of traditional database management system are:

1. Data redundancy: The data of a single record was present in a different place in different form and it was repeated in many ways.
2. Data inconsistency: When data in a file is changed it did not support other database or files.
3. Program –Data Dependence: The data were merely dependent on the program. Any change in the structure of database led to damage of data.
4. Data was not shareable: Data in different computers were personalized. They were not accessible from other computers and users.
5. Data integrity: The database integrity was not maintained.

References:

Khanal, R.C. Khanal, R.C. Computer Concept for XII. Pashupatigriha Marga, Thapathali, Kathmandu, Nepal: Ekta Books Distributors Pvt. Ltd., 2010. 39-44.

Adhikari,Deepak Kumar.,et.al., Computer Science XII,Asia Publication Pvt.Ltd