Database Normalisation Questions Medium
The process of converting an unnormalized database to a normalized database in database management is known as database normalization. It involves a series of steps to eliminate data redundancy and improve data integrity and efficiency.
The process typically includes the following steps:
1. Identify the functional dependencies: Analyze the data and determine the relationships between attributes or columns in the database. This helps in identifying the functional dependencies, which are the relationships between attributes that determine the values of other attributes.
2. Define the primary key: Identify a unique identifier for each record in the database. This primary key will be used to uniquely identify each record and establish relationships between tables.
3. Apply the First Normal Form (1NF): Ensure that each attribute in a table contains only atomic values, meaning that it cannot be further divided into smaller components. This eliminates repeating groups and ensures that each attribute has a single value.
4. Apply the Second Normal Form (2NF): Remove partial dependencies by ensuring that each non-key attribute is fully dependent on the entire primary key. This involves splitting the table into multiple tables if necessary.
5. Apply the Third Normal Form (3NF): Eliminate transitive dependencies by ensuring that each non-key attribute is only dependent on the primary key and not on other non-key attributes. This may involve further splitting the tables and creating additional relationships.
6. Apply higher normal forms (if required): Depending on the complexity of the database and the specific requirements, higher normal forms such as Boyce-Codd Normal Form (BCNF) or Fourth Normal Form (4NF) may be applied to further eliminate anomalies and improve data integrity.
7. Create relationships between tables: Establish relationships between the normalized tables using primary key and foreign key constraints. This ensures data consistency and integrity when querying or modifying the database.
8. Test and optimize the normalized database: Validate the normalized database by testing it with sample data and performing various operations. Optimize the database structure and queries for better performance and efficiency.
By following these steps, the unnormalized database can be transformed into a normalized database, which is more efficient, flexible, and less prone to data anomalies.