Syllabus Detail

  • Database types; centralised,distributed, local, online 12 ATAR

 

Background

  • A database is simply a collection of data or information
  • A database is constructed in such a way that the data stored is organised and allows for efficient retrieval
  • Database systems rely on the collection of schemas, tables, queries and reports
  • There are four types of common databases, including: centralised, distributed, local and online

 

Centralised Databases

  • A centralised database is a database that is located and stored in a single location
  • It differs from that of other databases due to its singularity
  • Centralised databases are often stored on one central computer or server
    • An advantage of this type of database is the ability to access all the information from one central location
    • A disadvantage of this type of database is the potential bottlenecking if multiple users are trying to access the database at once

 

 Distributed Databases

  • A distributed database is a database that is located across multiple locations
  • Different parts of the database are stored separately on multiple storage devices but controlled by the same DBMS (database management system)
  • Some types of DBMS's can be used to synchronize data across a distributed database as if the data were hosted in the same location
    • An advantage of this database type is the ability for users to work with specified parts of the database (hence ensuring security and performance improvements)
    • A disadvantage of this database type is the complexity of the database, as extra logical and physical design is needed for the implementation of a distributed database system

 

Local Databases

  • A local database is simply a database that is stored locally within an application, program or computer storage device
  • As the name suggests, the database is only accessible locally, and is often used to hold information such as Settings or program-specific information
    • An advantage of this database type is ability for total security - as the database can only be accessed locally and isn't susceptible to online attacks
    • A disadvantage of this database type is the fact that information stored on the database can only be accessed locally, and may not be ideal for certain applications or programs (such as web-based applications)
  • Developers often use local databases when developing and building applications
  • A local database can also be attached to an external device on a computer, such as a CD or external hard drive

 

 Online Databases

  • An online database is a database that is accessible only via the Internet or a network connection
  • Data is often stored in large data centres externally
  • Many modern websites take advantage of this service to utilise databases for the purpose of dynamic content on websites
    • An advantage of this type of database is due to the fact that the data can be accessed from anywhere an Internet connection is present
    • A disadvantage is the availability of the data - as if the host storage centre happens to go offline, the data becomes inaccessible

 

Further Research

  1. Read more about RDBMS's here
  2. Read more about the different types of databases here
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