Database Normalisation Questions Long
The process of eliminating domain-key dependencies in a database is known as database normalization. It involves organizing the data in a database in a structured and efficient manner to minimize redundancy and improve data integrity.
The first step in eliminating domain-key dependencies is to identify and define the functional dependencies within the database. Functional dependencies describe the relationship between attributes in a table, where one attribute is functionally dependent on another. This is typically represented using a functional dependency diagram or by analyzing the data and identifying the relationships.
Once the functional dependencies are identified, the next step is to apply the normalization rules to eliminate the dependencies. There are several normal forms that can be used to achieve this, including First Normal Form (1NF), Second Normal Form (2NF), Third Normal Form (3NF), and so on.
1. First Normal Form (1NF): In this form, the data is organized into tables, and each attribute within a table contains only atomic values. This means that each attribute should not contain multiple values or repeating groups. To achieve 1NF, the tables may need to be split or modified to ensure that each attribute contains only a single value.
2. Second Normal Form (2NF): In this form, the table should be in 1NF, and all non-key attributes should be functionally dependent on the entire primary key. If any non-key attribute depends on only a part of the primary key, it should be moved to a separate table along with the part of the primary key it depends on.
3. Third Normal Form (3NF): In this form, the table should be in 2NF, and there should be no transitive dependencies. Transitive dependencies occur when an attribute depends on another attribute that is not part of the primary key. To achieve 3NF, any such dependencies should be removed by creating separate tables.
The process of normalization continues with higher normal forms, such as Fourth Normal Form (4NF) and Fifth Normal Form (5NF), if necessary. These normal forms address more complex dependencies and aim to further reduce redundancy and improve data integrity.
It is important to note that normalization is an iterative process, and it may require revisiting and modifying the database design multiple times to achieve the desired level of normalization. Additionally, normalization should be balanced with the performance requirements of the database, as highly normalized databases may require more complex queries to retrieve data efficiently.
Overall, the process of eliminating domain-key dependencies in a database through normalization involves identifying functional dependencies, applying normalization rules, and iteratively refining the database design to achieve a structured and efficient data organization.