Databases

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Databases

• What are they?

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What is a database?

• telephone directory
• address book
• doctor/dentist patient records
• cinema bookings
• Internet!
• School data sheets on you!

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OKdont laughbut..

• One example of a database is a MP3 player. Ipods
  store files in the following system

Can you do any better? Add your own choice of
records to Task 1.
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Sorted!
Adam Ahmad Amy Charlie Christopher Danielle Dom Ed
ward James Lizzie Matthew Michaela Nathalie Robert
Ross Samantha Stanley Thomas Vincent
So now go to your worksheet and complete task 2!

• One great feature of databases is that it can
  SORT data into ORDER. Through many fields. Do
  you have the skills to do this yourself?
• Put the following data into Ascending order

OK so what are the 1st 5 names?
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Task 2 answers
So get the hint. A database can SORT a lot of
data QUICKLY into any order that you want
ascending or descending by any data fields
Q1 If this database was put into ascending order
by name who would be 1st and last in the
list? Bongo Tarsa Q2 If this database was
put into descending order by Type order who
would be 1st and last in the list? Zebra
Crocs Q3 If this database was put into into
descending order by age order who would be 1st
and last in the list? Gorilla Snake
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Data Types

• Alphabetic only letters are allowed.
• Example fieldsFirst name
• Colours
• Animal type

• Numeric only
• numbers are allowed
• Example fields
• Age
• Height
• Speed/m.p.h.
• Percentage

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Data Types

• Alpha_numeric this uses letters and numbers
  together.
• Examples
• Tutor Groups
• Postcode
• NI number

• Currency uses currency signs! Pound, dollar,
  Euro etc.
• Time hours, minutes, seconds
• Date day, month, year

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Data Types

• Boolean exam board favourite!
• This data type has only 2 choices for the PC user
  to select
• Examples
• Yes / No
• Male / Female
• On / Off

• Memo contains lots of words
• Container image, sound, video
• Auto-number this automatically generates a
  number every time a new record is created

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Now to your worksheet
Boolean!
alphabetic
Memo
alphanumeric
date
numeric

• Label your copy of this database file with the
  correct Data types.

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Types of Databases
OR in other words

• Flat File - A flat file database deals with one
  data file at a time. Each record contains the
  same field headings. The data held can be
  'interrogated' by carrying out searches and sorts
  and producing reports.
• Relational - Related items of data can be stored
  in separate files so that the data is accessed
  only when needed. This cuts down on the number of
  separate data items stored in the computer
  memory.
• Distributed - It is a large-scale relational
  database with on-line features for users to
  contact the system. A user has direct access to
  the database from his or her computer terminal.
  The database contacted could be miles away (even
  in a different country). The connection is
  through a WAN network through a modem. Access to
  a distributed database is strictly controlled,
  with users being allowed into specific parts of
  the system at a time. Security of the data is
  very carefully monitored.

The school database with Y11 student timetable in
it
The school class-room database that gives each
room, teacher, Year group subject for every
room, every lesson, for each day!
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Types of databases.

• Flat File your MP3 file, your mobile phone file
  of phone numbers only stores the USERS data
  under one file name.

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Relational Database

• Data is stored in separate files
• Examples include
• Police files database
• School database
• Travel Agents
• DVLA (car registration) linked to Insurance
  linked to police queries

• But who do these agencies link their database
  files to???

Hotel
Travel Agent
Airplane company
Car Hire Company
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Distributed Databases

• This is a large-scale relational database with
  on-line features for users to contact the system.
• Cinema bookings
• On-line supermarkets
• Travel Agents
• Secret service

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Computerised databases

• Can hold a vast amount of data
• Very fast to find a specific record
• Can easily search for a specific criteria e.g.
  "all of the people who live in Warwick
• Can perform analysis on the data e.g. most
  popular selling item
• Data can be sorted into ascending or descending
  order on any criteria
• Can easily update or amend a record e.g customer
  moves house
• Records are stored safely and are not easily lost
• Easy to make a back-up in case of data loss

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Paper-based databases

• Limited by physical storage space available
• Can take a while to manually search through all
  of the records
• Difficult to search for a specific criteria,
  every record would have to be manually looked at.
• Very difficult to analyse the data.
• Can only store data ascending or descending under
  one criteria e.g. surname
• Changes have to be done manually, records can
  look messy if scribbled out.
• Records can be lost or misfiled, making it hard
  to find them.
• Difficult to make a back up in case of data loss

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Which are manual which are computerised
database issues?
Complete the questions on your work sheet