Introduction to Data in DBMS

Data

A collection of raw facts and figures is called data. The word raw means that the facts have not yet been processed to get their exact meaning. Data is collected from different sources. It is collected for different purposes. Data may consist of numbers, characters, symbols or pictures etc.

Data is a vital resource for any organization. A resource is anything that is valuable for an organization. Resources include buildings, furniture, vehicles, machinery and employees. Data is considered a resource because it provides correct information for making proper and timely decisions. It enables the management of the organization to utilize other resources effectively. It is not possible to make a good decision if data is not available in the desired format.

Example of Data

1. When students get admission to colleges or universities, they have to fill out an admission form. The form consists of raw facts about the students. These raw facts are the student’s name, father's name, address etc. the purpose of collection or university.
2. During the census, the Government of Pakistan collects the data of all citizens. The government stores this data permanently to use for different purposes at different times.
3. Different organizations conduct surveys to know the opinion of the people about their product. In these surveys, people express their ideas and opinion of the people about different issues. These ideas and opinions of the people are stored as data. The organizations use this data for the improvement of their products.

 

Types of Data

      Data may be of the following types:

Number Data

      Number data consists of numeric digits from 0 to 10,245 or -5. The numeric type of data may either be positive or negative

Alphabetic Data

         Alphabetic data consists of alphabetic letters from A to Z, a to Z and blank spaces e.g. “IT Series”, “Computer” and “Islam” etc.

Alphanumeric Data

       Alphanumeric Data consists of numeric digits (0 to 9), letters (A to Z) and all special characters like+, %, and @ etc. like “87%”, “$300” and “H#17”.

Image Data

This type of data includes charts, graphs, pictures and drawings. This form of data is more comprehensive. It can be transmitted as a set of bits

Audio Data

          Sound is a representation of audio. Audio data includes music, speech or any type of sound.

Video Data

Video is a set of full-motion images played at a high speed. Video is used to display actions and movements.

Information

The processed data is called information. Information is an organized and processed form of data. It is more meaningful than data and is used for making decisions. Data is used as input for the processing and information is the output of this processing. This information can be used again in some other processing and will be considered as data in that processing.

For example, the marks of a student in different subjects are the data. To calculate the total marks, the marks of different subjects are used as data and total marks are the information. Now, to calculate the average marks of the student, this information will be processed again. in this processing, the information is used as data average marks will be the information.

Data   -> Processing -> Information

Example of information    

Some examples of information also follow:

1. In colleges and universities, the raw facts about students who live in Faisalabad, we will apply some processing on this data. This processing will give us the desired list. This list is a form of processed data and will be called information.
2. The data stored in the census is used to generate different types of information. For example, the government can use it to find the total number of graduates or literacy rate in the country etc. this information can be obtained by processing stored data. The government can use this information to take improve the literacy rate.

An organization can use the opinion of the people as data and process it to generate information of its interest. For example, it can know that how many people of the country are satisfied with the quality of its product and how many are unsatisfied. The organization can use this information for the improvement of its product.

Difference between Data and information

 

Data Data consists of unprocessed raw facts. Data is used as input in the computer. Data is not meaningful. Data is normally huge in its volume. Data is the asset of an organization and is not available to people for sale. Data is difficult or even impossible to reproduce. Suppose Government loses data of census. It is almost impossible to reproduce it. Data is used rarely. Data is an independent entity. Data is not used in decision-making

 

 

Information Information is the processed form of data. Information is the output of the computer. Information is meaningful. Information is normally short in volume. Information is normally available to people for dale. Information is easier to reproduce if lost. For example, if the list of illiterate citizens is lost, it can be reproduced easily from stored data. Information depends on data. Information depends on data. Information is very important for decision-making

Metadata

Metadata can be defined as data about data. It is used to describe the properties and characteristics of some other data. Metadata describes the size, format and other characteristics of data. It also includes the rules and constraints about data.

Example

        When you create a table, you specify the data type, size, format and other constraints for entering data in different fields of the tables. This is the metadata of the table. It describes the properties of the data to be stored in the table. Metadata is very important to ensure the integrity of the data.

 

Field name	Data type	Length	Description	Constraint
Roll No	Integer	3	Roll No of the student	Value from 1 to 100
Name	Alphabetic	50	Name of the student
Address	Alphanumeric	100	Address of the student
Email	Alphanumeric	25	Email of the student	Must contain@ and
Phone	Alphanumeric	25	Phone of the student

Table: Example of metadata

Roll No	Name	Address	Email	Phone
1	Ejaz	Faisalabad	ejaz@itseries.com.pk	784682
2	Usman	Faisalabad	usman@itseries.com.pk	727253

 

 

• Introduction to Databases