1.2.1 Databases

• Relational Database


  • Uses different tables for different entities
  • An entity is an item of interest about which information is stored
• Flat File


  A single file database based around a single entity and its attributes
• Database components


  • Relational Database
  • Flat File
  • Primary Keys
  • Foreign Keys
  • Secondary Keys
  • Entity relationship modelling
• Primary Key


  • The unique identifier which is different for each object added to the database
• Foreign Key


  • The attribute which links two tables together
• Secondary Key


  • Used to enable a database to be searched quickly
• Entity Relationship Modelling


  • One-to-one
  • One-to-many
  • Many-to-many
• Capturing Data


  1. Manually entered

  2. Scanned using methods such as Magnetic Ink Character Recognition (MICR)
• Selecting and Managing Data


  1. Data preprocessing

  2. Selecting data that fits certain criteria

  3. Using SQL to sort, restructure and select certain sections
• Exchanging Data


  1. Transferring the collected data

  2. Example: EDI (Electronic Data Interchange)