Databases - tools and techniques

Databases - tools and techniques

1. table characteristics

   • rows and columns
     • columns = field
     • rows = records
       • records
         • add
           • manually
           • external source
             • spread sheet
         • edit
         • delete
   • field types
     • currency
     • Boolean
       • yes/no
       • true/ false
     • web
       • hyperlink
     • lookup wizards
     • alphabetical
       • text
       • memo
     • numerical
       • numbers
       • currency
       • date/time
   • field size
     • byte
     • integer
     • long integer
     • single
     • double
     • decimal
   • field formats
     • fixed
     • decimal places
   • default values

2. validation

   • to check for errors
   • applies for a range
   • correct format
     • postcode
       • input mask
   • correct field sixe/data type
   • Validation types
     • check digit
       • the last one or two digits in the code are used to make sure the rest of the code is correct
     • format check
       • checks that data is in the right format
     • length check
       • checks data isn't too short or too long
     • look up table
       • looks up acceptable values in a table
     • presence check
       • checks that data has been entered, so that its not empty
     • range check
       • checks that values fall in a specific range
     • spell check
       • looks up words in a dictionary

3. indexing

   • primary key
   • foreign key

4. relationships

   • one to one
   • one to many
   • many to many