Introduction of DBMS

Introduction to Data, Database, Database System, DBMS

Data

Data is a collection of raw facts and figures which is isolated, uninterrupted, unrelated, and unorganized but able to organize into useful information. It represents alphabets[A-Z, a-z], digits (0-9), special characters(!, @, #, $ etc). E.g., Each student’s height in class is one piece of data.

Information

Information is processed, organized, and structured data that provides some meaningful output. Information of one thing may be data of another. Information comes from the data and takes the form of tables, graphs, diagrams, etc., and is stored in a computer as a file. E.g., The average height of the class is information.

Difference Between:

Data Information
Data is an unorganized, raw fact that needs processing, without which it is apparently random and useless. Information is processed, organized, and structured data that is useful to humans.
Data doesn’t depend on information. Information depends on data.
It doesn’t help to take decisions. It helps to take decisions.
It is measured in bits and bytes. It is measured in meaningful units like time, quantity etc.
E.g. Each student’s height in class is one piece of data. E.g. The average height of the class is information.

Database

A database is an organized collection of related information about a subject in a useful manner that provides a base for the procedure, such as retrieving information, concluding, and making a decision. A database is usually controlled by a database management system (DBMS).
E.g., School record of the student, product record, banking record of the customer.

Database System

A database system is a collection of interrelated data and application programs to access, update and manage the data.

Major uses of database application software are:

  1. Storing data
  2. Accessing data when it is required
  3. Updating/modifying data
  4. Deleting or removing data
  5. Providing security on the data so that it can be used only by the authorized person

Database Management System [DBMS]

It is a set of programs or computer software that manages data stored in a database. It allows users to retrieve, update, and manage the data. DBMS acts as an interface between user and data in a database.
E.g. MySQL, Microsoft Access, Microsoft SQL Server, FileMaker Pro, Oracle, and dBASE.

- Field

A database is a set of data values, of the same data type, in a table. It is also referred to as a column or an attribute. E.g. ID, First Name, Last Name, Address.

- Records

Each row of the table that contains data is called a record. It represents a complete information about particular entity.E.g. Ram 12 XII is a record of an entity set students.

- Objects

It is any defined object in a database that is used to store or reference data. E.g., Table, Index, View.

- Table

It is a collection of rows and columns. Rows represent records, and columns represent fields.

- Key

The key is a column value in a table that is used to uniquely identify a row of data or establish a relationship with another table.

Types of key:

  • Primary Key

It is a set of one or more attributes (fields) that can uniquely identify record within a table (relationship). E.g. Roll_no could be a primary key.

  • Candidate Key

There may be two or more attributes that uniquely identify an instance of an entity set. These combinations of attributes (fields) are called candidate keys. E.g., if Roll_no and Name are candidate keys which helps us to uniquely identify the student record in the table.

  • Alternate Key

A table can have multiple candidate keys. One key gets selected as the primary key among multiple candidate keys, and the remaining keys are known as the alternate or secondary key.
E.g., Both Roll_no and Name contain candidate key. If Roll_no is chosen as the primary key, the field Name is the alternate key.

Objectives of Database Management System [DBMS]

  • To provide storage area for mass amount of revalent data.
  • To make access to data easy for the end-user.
  • To provide a prompt/immediate response to the user’s request for data.
  • To allow latest modification to the database available immediately.
  • To eliminate data redudancy. [Duplication of data]
  • To allow multiple users to be active at the same time.
  • To protect the data from unauthorized access.

Advantages of DBMS

  • Data can be shared to different users.
  • It reduces duplication of data.
  • Data Integrity can be maintained.
  • Data Independence.
  • To allow multiple users to be active on same time.
  • It provides facilities for backup and recovery.

Disadvantages of DBMS

  • The initial investment is high for implementing hardware, software and training.
  • A fault in one part of the database, affects the other parts as well.
  • It is complex to understand and implement.
  • It requires trained and skilled human resources to operate the system.
  • Due to huge data size, it requires lots of space and memory to run application efficiently.