ICT databases

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  • Created by: buneme
  • Created on: 20-04-15 13:43
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  • Databases
    • Encoding data
      • Drawbacks
        • One letter codes can be confusing
      • Advantages
        • Faster to type in
        • More data can be displayed on screen
        • File size is smaller
    • Manipulating data
      • Creating a report
        • Formatted output from a database
      • Updating
      • Deleting
      • Searching
        • Also known as querying
        • Descending order
      • Sorting
    • Structure
      • Field: A column in the database
      • Record: A row in the database
      • File: A collection of related records
    • Data types
      • Text: Used for telephone numbers and text
      • Number: Integers & real numbers
      • Date/Time
      • Boolean - for yes or no answers
      • Autonumber - Often the key field to make each record unique
      • Currency - For numbers with a £ sign
    • General benifits and drawbacks
      • Benefits
        • Data can be edited more easily
        • Data is easier to back up
        • Data is easily shared
        • Data is easily transferred using networks
      • Drawbacks
        • Computers can be hacked leading to loss of data
        • Data can be copied quickly so personal data may be stolen
        • Loss of data due to power cut and hardware failure
        • Training needed to enable staff to access data
    • Validation
      • Data type check - Data has tyo be of a specific named type
      • Drop down list - restricts the user to a specific list of possible data
      • Format check - Data has to conform to the combination of charecters
      • Range check - Where a min & max values are set up
      • Definition - A rule set up to ensure that data entered is sensible
      • Length check - ensures exactly x charrecters are entered
      • Check digit - A number added at the end of a block of numbers, used to check that the numbers have been entered correctly
      • Batch - adds up meaningful data
      • Hash - Adds up meaningless data
      • Presence check - Data has to be entered into a field
    • Verification
      • Definition - Ensures that data sent is the same as the data sent is the same as the data recieved when data is transmitted between computers
      • Double entry - Checks if the same data, entered twice, matches
      • Visual check - When a user carefully reads what has been entered in and compares it with the original data source
      • Parity check - checks the data has been entered correctly compared to the source
    • Security issues
      • Password protection - stops unauthorized access
      • Password protocol - changing passwords regularly
      • Access rights - read only
      • Encryption - makes intercepted data unreadable
      • Saved off site - saved in a fire proof safe
      • Antivirus - prevents malicious progeams from damaging data
      • Physical security - lock doors
      • Firewall - prevents data been accessed by hackers

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