Syllabus Detail

  • Data duplication. 12 ATAR
  • Data redundancy. 11 ATAR, 12 GEN, 12 ATAR




  • Data duplication and data redundancy are similar concepts, but are not the same
  • Both concepts work to ensure efficiency and consistency in terms of databases and storage


Data Redundancy

  • Data redundancy occurs when the same data is entered in to two or more fields of a database
  • For example, "Joe" is entered in to the Name field under a record called Customers
  • "Joe" is also entered in to the Customer field under a record called Purchases
  • Although we are referring to the same Joe in both fields, each piece of data is seen as unique
  • This means that to update "Joe", we need to manually edit each reference
  • This differs from data duplication, as it is often not intentional and can take up potentially required storage space


Data Duplication

  • Data duplication occurs when an exact copy of a piece of data is created
  • For example, copy and pasting an item called "MyPicture.jpg"
    • The new pasted item contains the exact same data as the original picture
    • On different Operating Systems, the naming convention for copies will change (e.g. "MyPicture 2.jpg" or "MyPicture copy.jpg")
  • Data duplication provides benefits such as providing us with the ability to back up copies of files and create multiple verions of a file (which may be required for progress reporting or other information)
  • The duplication of data is often intentional and used primarily for creating backups
  • Data duplication on a database may result in data redundancy, and thus an inefficient and inconsistant database


Why are these important?

  • The act of normalising a database (organizing data to prevent redundancy) is critical to maintain an efficient and clean database
  • Ensuring unncessary data doesn't reside on the database allows for a consistent and accurate database
  • The ability to duplicate data intentionally allows us to create backups and maintain our data


Further Research

  1. Read more about Data Redundancy from DatabaseDev here
  2. Read more about Data Duplication from GeekInterview here
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