ICT Theory

ICT Theory

1. Relational Databases

   • Is an organised collection of data items with links between them structured in such a way that allows it to be accessed by a number of different application programs
   • Advantages
     • Improves Dara Integrity
     • Controlled Redundancy
     • Ensures Data Consistency
       • Data Independence
     • Security
   • Disadvantages
     • Complex to set up and maintain
     • Software is complex, expensive and needs a powerful computer.
     • All applications which access the data fail if the database fails

2. Normalisation

   • A staged mathematical process which removes repeated groups of data and inconsistencies. It is used to design a relational database in the most efficient way

3. Data Warehousing

   • A large Database used to store an organisations historical data which is used by the management information to extract information in order to help make a decision

4. Data Mining

   • The interrogation of data which is stored in the warehouse to find patterns in the data

5. Distributed Databases

   • Has data stored on a number of computers in different locations but appears as one logical database
   • Advantages
     • If data is lost on central site it can be reduplicated from the local site
     • Allows the sharing of data and the results of processing data
     • New locations can be added to the database without the need of rewriting the whole database
     • Faster response to user queries
   • Disadvantages
     • Software is more complex than on a centralised system
     • If data is transferred its more at risk from hackers
     • Heavy reliance on networks and communications
     • Security issues particularly if sensitive data is being transferred