Question

There are many benefits of using a database system to store data. Which of these statements is NOT a benefit of using a well-defined and normalised database?

1) Elimination of deletion anomalies
2) Elimination of redundant data
3) Elimination of duplicated data
4) Elimination of update anomalies

Answer 1

The elimination of duplicated data is not guaranteed by normalisation, as a well-defined and normalised database is designed to reduce redundancy but might still contain duplicates if data integrity isn't adequately managed.

Step-by-step explanation:

The statement that is NOT a benefit of using a well-defined and normalised database is the elimination of duplicated data because while normalisation reduces redundancy by ensuring that each data item is stored only once, it does not necessarily eliminate all duplicated data. Duplicates can still exist if data integrity is not enforced properly, for instance, if data entry allows for similar data with slight variations to be entered into the database.

Regarding the general approach to addressing the question:

1. One table is not intrinsically more correct than another; it depends on the specific requirements and constraints of the system. The 'correctness' of a table design is in relation to its ability to handle data consistently and effectively, without anomalies.
2. Grouping data differently could involve segmenting it into various normalised forms. The approaches to grouping can vary based on the level of normalisation desired. There are clear advantages to normalisation, such as easier maintenance and greater data integrity.
3. Switching between tables while addressing such topics is often a result of evaluating different normalisation scenarios, which can demonstrate the impact of changes on data redundancy and anomaly elimination.