Week 12

Week12

Relational Database

Revision

Today we study new lesson about Relational Database.

1.     Definition

Database is a collection of data stored that it is available to many users for different purposes.

• Database Management System is software for manipulating of database.

Database Components

Database Management System(DBMS)

There are 5 function of database;

1. Define, create and organise a database: The DBMS establishes the logical relationships among different data elements in a database and also defines schemas and subschemas using the DDL.
2. Input data: It performs the function of entering the data into the database through an input device (like data screen, or voice activated system) with the help of the user.
3. Process data: It performs the function of manipulation and processing of the data stored in the database
4. Maintain data integrity and security: It allows limited access of the database to authorised users to maintain data integrity and security.
5. Query database: It provides information to the decision makers that they need to make important decisions. This information is provided by querying the database using SQL.

Example of DBMS: Microsoft Access, Oracle, MySQL.

Type of Database Models

 

• Hierarchical data model organized data in the tree structured. This structure implies that a record can have repeating information, generally in the child data segments.   
  - The network model permitted the modeling of many-to-many relationships in data.
  -  In relational databases, fields can be used in a number of ways (and can be of variable length), provided that they are linked in tables. 
  In Database, a unique identifier called as Key Field.
  In the table of Database, Column named as Field and row named as Report.
  Database Terminology
  

  Field: A specific piece or category of data such as a first name, last name, city, state, subject or birthdate.

  Record: A group of related fields that describes a person, place, thing or transaction such as customer, student, location, product, or sale.

  Key Field: A field that contains unique information for each record, such as student ID for a student.

  Table:  A collection of records for a single subject such as Students, Products, or Sales.

  Relational Database: Multiple tables that are linked together to address a business process such as managing timetable, courses, and students.

  Object: The parts of an Access database that help you view, edit, manage, and analyze the data: tables, queries, forms, reports, macros, and modules.

  
  
  In Tutorial class we have done a small quiz about this lesson.