Data Structure

Database
Data is information - facts and statistics - collected together for reference or analysis.
A database is an organised collection of data. Look at the icons in the banner. Each icon is a database some of which you have used or heard about. You may have made your own database -

a birthday book, arranged by date, so you can look up and remember the birthdays of friends and family.
an address book arranged by surname.

or used

a Yellow Pages phone directory, arranged by profession, to find e.g. a gardener, baker, plumber...
a White Pages phone directory, arranged by surname, to find an address or phone number

You will hear the term DBMS. It means database management system. DBMS create databases to manage information. We will be using one called Microsoft Access.

Key: A. = Field; B. = File; C. = Record

Database Terminology

A character is the smallest unit of data and include letters, numbers and special symbols.
A field (A.) is a single item of information. The information can be numerical (e.g. 12756 km), text (e.g. the name 'Earth') or graphical (e.g. the picture of the Earth).
A record (C.) is a collection of fields. Records are usually sorted in some way (e.g. alphabetically, numerically or by date).
A file (B.) is a collection of records, usually on a common topic.

Quick Quiz 1

* Indicates required field

Name *

First

Last

Name *

First

Last

Class *

Email *

Class *

Email *

1. How many fields are on the first card? *

2.How many records are in this file? *

3. What is another word for data? *

5. How is this database sorted? *

4. Which one of these words is not an internet based database. Facebook, Google, Australian Census, Royal National Park, or Geneology Records *

6. Suggest a title for this file. *

Submit

Data Types
Fields can contain almost any sort of information,from a telephone number to a street address,photograph or written description (text). The most common data types are:

Text: for mixtures of words, numbers and symbols (e.g. names and addresses).
Number: for numbers only (e.g. weight, distance, serial numbers).
Date / time: for calendar dates and time (e.g. birth dates, lap times).
Currency: for money values (e.g. cost of products, bank balances).
Graphical: for pictures, diagrams or photos (e.g. identity pictures, supermarket product photos).

Quick Quiz 2

* Indicates required field

Name *

First

Last

Name *

First

Last

Class *

Email *

Class *

Email *

Use this specimen Australian passport to answer the next 4 questions.

1. What data type is her date of birth? *

2. What data type is her name? *

3. What data type is her photo? *

4. What data type is her nationality? *

This record is out of a database storing information about the moons in our solar system. Use it to answer the next 5 questions.

5. What data type is the 'Gravity (Earth=1)' field? *

6. How many text data type fields are there? *

7. What data type field is the information ' 3.551 days' in? *

8. What data type is the photo of Europa? *

9. What do scientists believe Europa is made of (composition)? *

Submit

Differences between Databases and Spreadsheets

A spreadsheet is an application for tabulating data while a database is where data is stored so that it can be retrieved by users.
The amount of data that is usually stored in a database is way more than what is contained in a spreadsheet.
A spreadsheet is edited directly by people while a database is accessed by applications that enter and modify data.
A spreadsheet is usually used for presentations and paperworks often involving number crunching while databases are commonly used in cases where a lot of data needs to stored.