Data Types

Data Types

1. Text

   • Telephone numbers need to be stored as text
     • they can not be stored as integer as they normal start with 0 the integer format will discount the 0
     • The other reason you wouldn't format as an integer as you less

2. Number

   • Integers
   • Currency

3. Boolean

   • Holds one of two allowed values
     • For example yes/no, True/false
   • Boolean data is used to answer question where there are exactly two option

4. Validation

   • Check Digit
   • Format check
   • Double checking
     • This is time consuming which means this is costing money
   • Proof reading
     • This is time consuming which means its costing money
   • Range check
     • Checks that data entered is between two figures
     • A secondary school may use range check for age of student between 11-16
   • Length check
   • Spell check
   • Validation can not check that data is correct
   • Look up table
   • presence check

5. Data can be stored in many different formats called data types

6. Images

   • Databases allow graphical images e.g. photographs to be stored as a data type
   • Different file types such a .jpg, .bmp, .tiff
   • Images are binary files rather than text or number this is why specific data is required