Database Normalisation Questions Medium
Data anomalies refer to inconsistencies or irregularities that can occur in a database when it is not properly normalized. These anomalies can affect the accuracy, integrity, and reliability of the data stored in the database.
There are three main types of data anomalies that can occur:
1. Insertion Anomalies: Insertion anomalies occur when it is not possible to add new data to the database without also adding unrelated data. For example, if a database is not properly normalized and a new customer record cannot be added without also providing information about the products they have purchased, it would be an insertion anomaly.
2. Update Anomalies: Update anomalies occur when updating data in the database leads to inconsistencies or duplication of data. For instance, if a customer changes their address and the database is not properly normalized, the address would need to be updated in multiple places, leading to potential inconsistencies.
3. Deletion Anomalies: Deletion anomalies occur when deleting data from the database unintentionally removes other related data. For example, if a customer record is deleted and it also contains information about the products they have purchased, the deletion of the customer record would result in the loss of the purchase history.
These anomalies can lead to data inconsistencies, redundancy, and inefficiencies in data retrieval and manipulation. By normalizing the database, these anomalies can be minimized or eliminated, ensuring data integrity and improving the overall efficiency and effectiveness of the database system.