Types of databases

Types of databases

1. Flat

   • Flat databases consist of one table that contains all the information and repeats lots of data rather than using item codes. This produces mistakes and problems with changing data.

2. Relational

   • These databases are many tables that only hold one particular type of data e.g. customers, items. These are then linked together with another table that only uses foreign keys referring to the primary keys in smaller tables which prevents redundant data. Simplicity means less mistakes will be made and small modifications only require one change.
   • Split into discrete entities based on the real world.
     • Entities are described by a series of FIELDS
     • Entities are connected by a series of relationships shown by an entity relationshipdiagram

3. Local Databases

   • Local is only used by one computer or device. this would be used for private information or sensitive information or perhaps very small businesses
   • Disadvantages: t everyone can see the information so would have to be distributed manually
   • Advantages: -Can privatise information -serves its purpose

4. Network databases

   • These databases are available to the whole of the network but can restrict access to parts of the network, they would be used in business' for employee information or stock information
   • Advantages are that these can be viewed by everyone and access can be restricted however, some nformation might be too sensitive to let people see. networks can be hacked.

5. Online

   • Why are they used?
     • They are used to store information online and to keep users updated about the database, this could be stock, worker schedule or details of clients/users.
     • advantages/disadvantages: These networks are good for use with customers as they can log in and view updated data however, they rely on the internet and connection speed/ bandwidth could make a difference to usage. If they are not properly maintained they could be subject to the internet changing them or using them for malpractice.
   • Examples
     • Tesco's
     • Amazon
     • Sony
     • Facebook (login details)