Database Normalisation Questions Medium
The process of converting a denormalized table to a normalized table is known as database normalization. It involves breaking down the denormalized table into multiple smaller tables, each with a specific purpose and containing only relevant data. This process helps eliminate data redundancy, improve data integrity, and enhance overall database performance.
The steps involved in converting a denormalized table to a normalized table are as follows:
1. Identify the functional dependencies: Analyze the denormalized table to identify the functional dependencies between attributes. Functional dependencies determine the relationships between attributes and help in determining the appropriate normalization level.
2. Determine the normalization level: Based on the identified functional dependencies, determine the normalization level required for the table. Normalization levels range from first normal form (1NF) to fifth normal form (5NF), with each level having specific requirements for data organization.
3. Create new tables: Create new tables based on the identified functional dependencies. Each table should have a primary key that uniquely identifies each record. Split the attributes of the denormalized table into these new tables, ensuring that each table represents a single entity or concept.
4. Define relationships: Establish relationships between the newly created tables using primary key-foreign key relationships. This ensures data integrity and maintains the associations between related data.
5. Eliminate data redundancy: Remove any redundant data by referencing the appropriate tables using foreign keys. This helps in reducing data duplication and improves data consistency.
6. Normalize further if required: If the denormalized table still contains any repeating groups or multivalued dependencies, further normalize the tables to higher normalization levels. This may involve creating additional tables and establishing new relationships.
7. Test and validate: Validate the normalized tables by inserting sample data and performing queries to ensure that the data is correctly organized and retrievable. Test the performance of the normalized tables to ensure that the database operates efficiently.
By following these steps, a denormalized table can be successfully converted into a normalized table, resulting in a more efficient and structured database design.