Group 6
• What is data redundancy? Data redundancy occurs in
database systems which have a field that is repeated in two or
more tables. . .
• Data redundancy leads to data anomalies and corruption and
generally should be avoided by design.
• Data normalization prevents data redundancy, and it also
makes the best possible usage of storage.
• Isolated data is a problem because it often is difficult to access
data stored in separate files in different departments. The book
uses this example- Assume that the student e-mail addresses
exist in the Student files, and class room numbers (locations) are
in the Schedule of Classes file. To send an e-mail message
informing students about a room change, data is needed from
both the Student file and the Schedule of Classes file,
complicating things unnecessarily.