Sixth Chapter Lesson-1 Concept of Database.

In this Lesson you will learn-

  • 1. Concept of data and information.
  • 2. Basic elements of database.
  • 3. Advantages and disadvantages of database.
  • 4. Application areas of database.

 

Data:  Data is raw, unorganized facts that need to be processed. For getting desired output in a processing data is used as input. Data can be defined as a representation of facts and it is the smallest part of information. Data is represented with the help of characters such as alphabets (A-Z, a-z), digits (0-9) or special characters (+,-,/,*,<,>,= )

Classification of data:

Information: When data is processed, organized, structured or presented in a given context so as to make it useful, it is called information. Information is the processed data on which decisions and actions are based.

Examples of data and information: The marks of every subject of a student is called data. On the other hand, the report or result of a student by calculating the marks of all subjects is called information.

 

Database: A database is an organized collection of related data, stored and accessed electronically. A database is used by an organization as a method of storing, managing and retrieving information. Modern databases are managed using a database management system (DBMS).It may have single or related multiple table in a database.

The elements of database:

  • Attribute/Field/Column: A field is a part of a record that contains a single piece of data for an object in the record. On the other hand, the columns of a table are called attributes, which are the describing characteristics of each record.
  • Attribute value: The value of a particular attribute is called attribute value.
  • Entity/Record/Tuple/Row: A record is a group of fields within a table that are relevant to one particular person, company, or item in a database. Records appear as rows in the database table.
  • Table/Entity set: A database table is composed of records and fields that hold data. Tables are also called datasheets. Each table in a database holds data about a different, but related, subject.

 

Data Hierarchy: Data hierarchy is a systematic organization of data mainly in a hierarchical form. Data organization basically involves bit, byte, field, record, file, and database.

 

Advantages and disadvantages of database:

Advantages:

  • 1. Reduced data redundancy
  • 2. Reduced updating errors and increased consistency
  • 3. Greater data integrity and independence from applications programs
  • 4. Improved data access to users through use of host and query languages
  • 5. Improved data security
  • 6. Reduced data entry, storage, and retrieval costs
  • 7. Facilitated development of new applications program

Disadvantages:

  • 1. Database systems are complex, difficult, and time-consuming to design
  • 2. Substantial hardware and software start-up costs
  • 3. Damage to database affects virtually all applications programs
  • 4. Extensive conversion costs in moving form a file-based system to a database system
  • 5. Initial training required for all programmers and users

 

Application areas of database:

  • 1. Banking
  • 2. Airlines
  • 3. Library
  • 4. Telecommunication
  • 5. Educational Institution
  • 6. Production and distribution
  • 7. Human Resource (HR)
  • 8. Automated Teller Machine (ATM)
  • 9. Stock/Share Market

 

Lesson evaluation- 

  • a. What is data?
  • a. What is information?
  • a. What is database?
  • a. What is attribute/field?
  • a. What is field/entity/record?

 

  • b. Field and record are not same-explain it.
  • b. Field is not dependent on record- explain it.

 

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