Database

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Database

• What is a Database?

A database is a collection of related data items,
which are linked and structured so that the data
can be accessed in a number of ways.
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Examples of Databases

• Our library system Mrs King scans in your
  library book or card, via the barcode reader as a
  data capture method, to access information about
  the book or you.
• GCSE results The examination boards keep
  details of examination results and student
  records.
• Doctors keep patient records and appointment
  details.
• BT keeps details of customer telephone numbers
  that can be accessed via Directory Enquiries.

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How is a Database constructed?
TABLES
Entities are made up of Attributes An attribute
is called a field
Tables are made up of Records A record is an
Entity
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Data Types
Fields are made up of different data types.
There are many different data types
eg Text Number Date/Time Currency Auto
number Yes/No OLE Object Hyperlink Lookup Wizard
What data types are used in the Student Table?
What data type would we use for Telephone Number?
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Field Properties
When we have chosen the Data Type It is
important to set the properties. The properties
cover a host of different things from how the
data is displayed to the field size. Date, for
example, can be displayed in long, short or
medium format, ie 08 March 2003, 08/03/03, 8 Mar
03. Data can be validated so that only acceptable
data is allowed in a field, eg 8. Currency can
be displayed in Integer format or to a number of
decimal places. DESIGNING YOUR DATABASE IS THE
MOST IMPORTANT PART RUBBISH IN RUBBISH OUT
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Field Properties
What field properties have been used in this
example?
Gender Field size is 1
Student Registration No field size is 6
Validation only data which has three letters
and three numbers will be accepted
Date/Time is set for short date
Field sizes for Surname and Christian Name are
normally set at 25 characters some people have
double barrelled names
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Primary Keys
A table normally has a Primary Key ? A Primary
Key is a unique identifier You all have unique
identifiers, for example your NHS No. NIN
(National Insurance Number) Student Registration
No.
Why dont we use Names or Dates of Birth as a
Primary Key?
Which Field is the Primary Key?
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Relational Database
Student Details Table
TABLES STORE THE INFORMATION A DATABASE CAN
HAVE MANY TABLES WHICH ARE LINKED TOGETHER THESE
ARE CALLED RELATIONAL DATABASES
1
?
Course Details Table
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Benefits of Relational Databases

• We use relational databases to store vast amounts
  of logically related information
• Information can be stored in separate tables
• Queries or interrogating the database will allow
  all linked tables to be accessed as one
• Reports can be used to display the results

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Microsoft Access

• The relational database software we are going to
  learn to use is Microsoft Access
• This software is part of the Office Professional
  suite of programs that we have been working with,
  ie Word, PowerPoint.
• Benefits of using a suite of programs is that we
  can exchange information between the programs