What is a
database?
-
It is an organized collection of data or a
mechanism of storing, managing and retrieving information.
-
It is applied in hospitals, colleges or
universities and bank.
Functions of
Database
-to store
-to organize
-to control
Database
Components
Data Item- it is a piece of information
Schema-
it describes the organization of data and its relationship within the database.
The schema consists
of definitions of the various types of record in the database, the data-items
they contain and the sets into which
they are grouped.
Database
Architecture
1.
The architecture of a modern database consists
of:
2.
Actual database (contents)
3.
Hardware to process and store the data
4.
Software to manipulate the contents
5.
People to administer the access, control and
modification of data
Database
Management System
It is a software package for manipulating databases or simply it
is a database program.
Examples of Database Management System
1.
MySQL
2.
Microsoft
Access
3.
RDBMS
4.
Clipper
5.
Oracle
6.
SQL
Server
7.
PostgreSQL
8.
FileMaker
9.
dBASE
10.
FoxPro
Features
of DBMS
1.
It allows users to create new database
2.
Give users the ability to query& modify the
data using appropriate language (query language or data manipulation.
3.
It provides information to the decision makers
that they need to make important decisions.
Types
of Languages
1. DDL
(Data definition language)
2. DML
(Data manipulation language)
3. Structured
Query Language (SQL)
Components
of DBMS
1. Field-
it is a specific piece of data such as a first name, last name,
city, state, subject or birthdate.
2. Record-
a group of related fields that describes a person, place, thing or transaction
such as customer, student, location, product, or sale.
3. Table-
a collection of records for a single subject such as Students, Products, or
Sales.
4. Key
Field- a field that contains unique information for each record such
as Student ID card.
5. Relational
Database- these are tables that are linked together to address a
business process such as managing timetable, courses and students.
6. Objectives-
it helps you view, edit, manage and analyse the data in the database.
Entity
Relationship Diagram
-
It describes the relationship of data in key
columns and is shown in the form of diagram.
It has three
types of relationship:
1. One
to one (1:1)- each row in one database table is linked to 1 and only
1 other row in another table.
2. One
to many (1:M)-
each row in the related to table can be related to many rows in the
relating table.
3. Many
to many (M:N)- one or more rows in a table can be related to many
rows in another table.
DBMS
Users
•
End
Users
•
Application Programmers
•
Database Administrator
Database
Models
Data model of database:
-
Structure
-
Characteristic
-
Description
-
Organization
Types
of Database Models
•
Hierarchical database- it organizes
data in a tree structure that may establish one to many relationship.
•
Network
database-it represents complex data relationship, and the data are represented
by showing links among them.
•
Relational
database- the data is organized in the form of rows and columns as in a table.
•
Object-relational
database
Types of Database
•
Individual
(primarily used by one person)
•
Company/shared (stored on a mainframe by a
computer professional)
•
Distributed (stored in not just one location
but in several locations)
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