Database Normalisation Questions Medium
Referential integrity is a fundamental concept in database normalization that ensures the consistency and accuracy of data relationships between tables. It is a set of rules that define and enforce the relationships between tables through the use of primary and foreign keys.
In a relational database, referential integrity ensures that any foreign key value in a table must match a primary key value in another related table. This means that every foreign key value must have a corresponding primary key value in the referenced table, or it can be null if the relationship is optional.
The purpose of referential integrity is to maintain data integrity and prevent inconsistencies or anomalies in the database. It helps to enforce data integrity constraints and maintain the accuracy and validity of the relationships between tables.
By enforcing referential integrity, the database management system (DBMS) ensures that any changes made to the primary key values in the referenced table are properly reflected in the foreign key values in the related tables. It also prevents the creation of orphaned records, where a foreign key value references a non-existent primary key value.
Referential integrity can be enforced through various techniques, such as using primary and foreign key constraints, cascading updates and deletes, and triggers. These mechanisms help to maintain the integrity of the data relationships and ensure that the database remains consistent and reliable.
In summary, referential integrity is a crucial aspect of database normalization that ensures the accuracy and consistency of data relationships by enforcing rules and constraints on the use of primary and foreign keys. It helps to maintain data integrity and prevent anomalies, ultimately leading to a well-structured and reliable database system.