Database

Database

1. Data types

   • Number
     • Real/integer
       • Picture
         • Video
       • Sound
   • String/text
   • Data/time
     • Lists
   • Currency
     • Boolean
       • T or F
   • Data integrity
     • Input into the system by using verification techniques

2. Validation

   • Primary key
     • Unique identifier
   • Checks
     • Range
       • Test is out of 40 then only marks in the range 0-40 are available
     • Type
       • Ensure data is the correct type
         • A jar of jam can't weight £3
     • Format
       • If a data has a pattern e.g. ME3 4AD
     • Length
       • Usually a forename is between 2-18 characters long
     • Presence
       • Data must be entered
     • Lookup
       • Grade goes A*-U, a W cannot be entered
   • Reports
     • A printed document, contains data from the database
   • Forms
     • Make data look good and secure
   • Reduce amount of errors. It checks data is sensible and reasonable

3. Acces

   • Query
     • specifies what records you are searching for and what fields from the records
   • Complex query
     • looks at data with multiple crieria
   • If data is secure
     • Not destroyed
       • not altered
         • not fall in unauthorised people
   • Field
     • To define a new field, you give it a name e.g. Surname, address etc
   • Record
     • Records are composed of fields, each of which contains one item of information
   • File
     • Consists of records
   • Wildcard
     • Is used in a query to stand for any character you don't know exactly

4. Security

   • Back-ups
     • Saved on to removable data- second copy
   • Password
     • A method of authentication
   • Businessess
     • If not secure
       • payments for goods not being received
         • Bad publicity
   • Benefits of databases
     • Fast access
       • Easy to edit
         • Sharing
           • Security
         • Updated or changed