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 addresses exist in the Student files, and class room numbers (locations) are in the Schedule of Classes file. To send an message informing students about a room change, data is needed from both the Student file and the Schedule of Classes file, complicating things unnecessarily.