What is a database

1
What is a database?

• Store of information (data)
• on paper, on computer, card index
• Data is organised and structured
• this allows data to be easily located
• Manual databases
• telephone directory (organised by surname)
• library card index (organised by subject)

2
Storing computer databases

• Depending upon their size, databases will be
  stored on
• floppy disc
• hard disc
• CD ROM
• a database stored on CD cannot be altered

3
Benefits of Computer Databases

• Computer databases allow
• rapid searching
• ie finding a particular record
• sorting
• according to specified field(s)
• multiple copies to be printed

4
Database Structure

• FILE Record Field

A file consists of individual records. A record
holds related data items. Each piece of
information in the record is called a field.
5
Planning a Database

• Creating a database
• Be clear about the type of information to be
  stored
• Involves planning the field types and structure

6
Planning a Database

• General purpose databases can hold different
  types of data
• national insurance number
• eg WC 45 61 74 D,
• date of birth
• postcode
• eg EH54 6HW

7
Field Types

• Text
• used to store only letters (alphanumeric)
• Numeric
• used to store number eg 1.234 456.875
• Integer
• used to store whole number, eg 1 3 56 987
• Date

8
Searching a Database

• to pick out data
• sometimes called find
• according to a specified criteria
• eg locate all the people called Smith

9
Sort

• Places records into order
• eg alphabetical, numerical
• A simple sort will put records into order based
  on one field

10
Complex Sort

• Allows data be sorted on 2 (or more) fields