Data Management

Data Management

1. Data types

   • Number Formats
     • Integer
       • Positive or negative whole numbers (no decimal places), eg 1, 2, 3
     • Currency
       • Usually displayed using two decimal places with currency symbol eg £150.00
     • Percentage
       • Displays the value as a percentage eg 20% 
     • Fraction
       • Displays the value as a fractions eg 1/4 
     • Decimals
       • Displays the value as a decimal place used can be set, eg 1.66
   • Text
     • Alphanumberic data which can contain letters and numbers, but not designed to be used for calculations e.g 48 Boston Road
   • Date
     • Displays data information using an appropriate format as defined by the user. the format can be customised in terms of detail and type, for example 1st December 2010 or shortened to 01/12/10 (UK), 12/01/10 (USA)
   • Time
     • Displays time information using an appropiate format as defined by the user. Like with Date, the format can be customised according to the type required, for example 14:30 (24 hour) or 2:30 (12 hour)
   • Limited-Choice Options
     • Drop-down lists, radio buttons and tick lists can be used to offer a limited choice of data values. these are validation methods and are particularly useful for data entries.
   • Boolean
     • Can only hold True/False (or Yes/No) value.

2. Encoding Data

   • During data entry, data may be encoded. A number of different codes are defined for the for the data. For example a gender field may be stored as codes (e.g. 'M' for male, 'F' for female)
   • The benefits
     • 1
       • Speeds up data entry as the data is often a single letter.
     • 2
       • Less data, requiring less storage space to save, resulting in faster retrieval of information.
     • 3
       • Easy to validate, and prone to human error during data entry.