Types of Databases

Types of Databases

1. Flat Databases

   • Consists only of one table
   • A lot of mistakes can be made in these databases as they store repeated data throughout
   • Also, the information is not linked so when there are updates, not all of the data will alter

2. Relational Databases

   • Links all the information together from different tables without having to repeat data in a single table
   • Advantages
     • Mistakes are minimised when handling large amounts of data
     • Different levels of access-
   • Features
     • Information separated into discrete entities
       • Based on the real world
       • e.g. employees, product, order
     • Entities are described as a series of fields
       • Describes the structure of the entities
       • e.g. product name, weight, price
     • Entities are connected by a series of relationships
       • Built using common field
       • Represented by entity relationship diagram (ERDs)

3. Local Databases

   • Only one person can access this database
     • The one person will need a password and some kind of account to be able to access it
     • There will still be a certain level of access for the person on the database
   • Advantages
     • Information that people might not want to share can be kept private
   • Private data e.g. finances

4. Network Databases

   • More than one person can access it
     • Those people will need a password and some kind of account to access it
   • Information that one than one person needs can be accessed by them

5. Online Databases

   • Examples
     • Tesco
     • eBay
   • Why are they used?
     • They are used to store information
       • Tesco and eBay need to be able to store customer details, sales, etc.
   • Advantages
     • Less mistakes are likely to be made
   • Disadvantages
     • As they are big companies, there will be a lot of information/ data to go on those databases