Database Normalisation Questions Long
The purpose of functional dependencies in database normalization is to ensure data integrity and eliminate data redundancy. Functional dependencies define the relationships between attributes in a database table, indicating how the values of one or more attributes determine the values of other attributes.
By identifying and establishing functional dependencies, we can organize the data in a way that minimizes redundancy and anomalies, leading to a more efficient and reliable database design. Functional dependencies help in achieving the following goals of normalization:
1. Elimination of data redundancy: Redundancy occurs when the same data is stored in multiple places, leading to inconsistencies and wastage of storage space. By identifying functional dependencies, we can eliminate redundant data by storing it only once and referencing it wherever needed. This reduces the chances of inconsistencies and improves data integrity.
2. Minimization of update anomalies: Update anomalies occur when modifying data in one place leads to inconsistencies or errors in other places. Functional dependencies help in identifying and resolving such anomalies by ensuring that updates are made in a consistent and controlled manner. This ensures that the database remains accurate and reliable.
3. Simplification of data retrieval: Functional dependencies help in simplifying data retrieval operations by organizing the data in a logical and structured manner. By understanding the dependencies, we can design efficient queries that retrieve the required information without unnecessary complexity or duplication.
4. Facilitation of database maintenance: Functional dependencies aid in maintaining the database by providing a clear understanding of the relationships between attributes. This makes it easier to modify the database schema, add or remove attributes, and ensure that the changes do not introduce inconsistencies or anomalies.
Overall, functional dependencies play a crucial role in the normalization process by guiding the design of a well-structured and efficient database. They help in achieving data integrity, reducing redundancy, minimizing anomalies, simplifying data retrieval, and facilitating database maintenance.