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Creating Learning Networks for African Teachers

UNESCO PROJECT (Contract No. 408.302.9)

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Background

COMMON APPLICATIONS

Spreadsheets
Tutorial
Introduction
Worksheets
Columns & Rows
Charts

Examples
Refraction of Light
Solving Polynomial Equations
Workers' Database
Base Converter

Activities

Links

Databases
Tutorial

Introduction

Example
Periodic Table

Links

Word Processing
Tutorial

Introduction
Text
Page Properties
Printing
Quit

Examples
Address list
Time table
Newsletter
Repeat Patterns
Logos

Practical Questions

HTML Editors
Tutorial
Basic html
Netscape
Composer


Examples
Teaching Syllabus
Teachers' Notes
Subject Website Lists
Students Website

Art
Principles of Art
Elements of Art
Coloured Pencil Paintings
Pastel Paintings
Book cover
Posters


Scanning an image


DATABASE TUTORIAL

INTRODUCTION TO DATABASE CONCEPTS AND TERMINOLOGY

Definitions

A database is collection of information, such as an address book. Whenever you access a database, whether it be to add new information, get information, change information, or transform the information into some meaningful order, you are managing the database.

Suppose you have the address book. Each section in the book contains the name, address and phone number of an individual. The book contains three lines of information: (1) Name, (2) Physical address,  and (3) phone number as shown below:
 
Malinzi J.K. Steve 

40 Acacia Avenue 
Kololo, Kampala 

041 355 524 
 

Fred & Wilma Flinstone 

33 Yusuf Lule Road 
Nakasero Kampala 

071 777 890

A database is an integrated collection of related files along with details of the intepretation of the data contained therein.


Types of database systems

Basically there two catagories of databases systems:

(a) Electronic/computer based database:
A computer-based database system such as Microsoft Access, Clipper, Fox-pro, Database III & IV perform these types of operations on a database that is stored on a computer disk.

It allows you to:

  • Add new empty files to the data base
  • Retrieve data into existing files
  • Insert new data in the existing files
  • Update data in the existing files or transform data into meaningful information
  • Remove existing files from the data base

 Examples of uses of electronic databases:
-Photo gallery (online photo album)
-A cache engine (where book marked internet resources are kept for future reference).
-Personal database showing names, location and phone number.


                        This  cross-section is an example of Personal database.
 

(b)Manual database systems:

Paper databases are referred to as files. When using a computer, however, we refer to them as either files or tables, depending on the program. Microsoft Access refers to them as tables.
The term is used in connection to the unique design that all databases use, being organised in columns and rows.

Examples of manual database:

-Box of library catalogues: The catalogue is a record that can be referenced to find out which book was taken, when it was taken and when it would be returned to the library.
-A file showing marks of a student : The records here are: Name of student, class, marks per subject and possibly the total.
-Dictionary
-Diary book is a database of your friend's addresses.
-Encylopedia
Whatever the type of a database, the major objective of it is for record-keeping, so that these records are referenced whenever need arises.
However, tasks that may take you days doing the operation manually may take the computer only a few seconds to accomplish.

Database system:

A database system is a computerised record-keeping system whose overall purpose is to record, retrieve and maintain information.


Components of a database system
:

(a) Users of the data base system

(b) Data:

Data is of various types:
 (i) Text data types: used to store non-numeric type of information like names, address etc.,
        and the maximum length it can take is 256 characters.

(ii) Numeric data type: used to store numbers of digits, including (-) and decimal point.(.)

(iii) Date: used to store date. Format of storing date is either mm/dd/yr or dd/mm/yr.
       Date is automatically checked for validity without programmers intervention.

(iv) Logical data type: Used to store one of the two conditions. (True/False, Yes/No or  F/M)

(v) Memo fields: These are stored in files outside the actual data base file. Memo fields can
      be used as a variable in the main memory unlike other types.

(c) Software: This is an interface between the system users and the
       physical  database itself. Some of the database system softwares include:
       Microsoft Access
       Fox-pro
       Clippers
       Data base 111 & 1v etc

(d) Hardware


Why do we need databases?

It's now clear that a database consists of records, and in any instutition, company or organisations record-keeping is very important. Therefore, an organisation, company or institution, if any, without records is absolutely undefined, and it's not worthy being called what it claims to be. For record-keeping,organisational structure and easier and fast  access of information is the major reason why any company, organisation or institution needs a database.

How does one create a database file?

There are  few steps to follow and you get the work done: We shall restrict ourselves to Microsoft Access in creating a data base file, the steps required  are here outlined below. We shall begin by creating a database structure/table; which defines the names of various fields, Data types and the length for each field as illustrated below:

(i) Database structure
When storing information within a database table, each piece of data must be stored under unique field name as shown below:.
 
Field name Data type Length
Name Character 15
Amount Numeric 10
Sex Logical 1

 

(ii) Start a database program:

Start--->  programs---> Microsoft Access. The screen below is automatically displayed:

Click on Blank Database to create a new database.

Click on Blank Database----> Ok

Click on Table then New.
 

Click on Table then New. The screen below is displayed:

When you choose "Design view", a table is displayed prompting you to fill the required data: Field name, Data type and the Field Description.


 

Example of a database design:

A director of studies in one Secondary School in Uganda would like to etablish a database of all student biodata .This example is already designed for you.
Click here to view the worked out database design -> Click Table and select STUDENT BIODATA.
 
Using that database one can query the following:
(a) List either Congolese or Ugandans who are orphans
(b) List all students above 13 years of age and are female.
(c) List students above 11 years of age and are male
(d) Select all American students above 11 years of Age
(e) Select all Tanzanians or Rwandese above 10 years but below 17 years.
(f) Select all Ugandans who are male.


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