Database Normalisation Questions Long
The purpose of foreign keys in database normalization is to establish and maintain relationships between tables in a relational database.
Foreign keys are attributes or columns in a table that refer to the primary key of another table. They create a link between two tables, allowing data to be shared and referenced across multiple tables.
The primary purpose of using foreign keys is to enforce referential integrity, which ensures that the relationships between tables are valid and consistent. By using foreign keys, we can prevent the creation of orphaned records or data inconsistencies.
Foreign keys also play a crucial role in maintaining data integrity and improving data quality. They help in avoiding data duplication and redundancy by promoting data normalization. By breaking down data into multiple related tables, we can eliminate data redundancy and improve data consistency.
Additionally, foreign keys enable the implementation of various database constraints, such as cascading updates and deletes. Cascading updates allow changes made to the primary key of a referenced table to automatically propagate to the foreign key values in other tables. Cascading deletes ensure that when a record is deleted from the referenced table, all related records in other tables are also deleted, preventing orphaned records.
Foreign keys also facilitate the creation of joins between tables, enabling the retrieval of data from multiple related tables in a single query. This allows for efficient data retrieval and analysis.
In summary, the purpose of foreign keys in database normalization is to establish and maintain relationships between tables, enforce referential integrity, improve data quality, prevent data duplication, enable cascading updates and deletes, and facilitate efficient data retrieval through joins.