Data integrity refers to the accuracy, consistency, and reliability of data throughout its lifecycle. It is a critical aspect in the design, implementation, and usage of any system that stores, processes, or retrieves data.
There are various aspects of data integrity, including entity integrity, referential integrity and domain integrity.
data integrity
Entity Integrity
Entity Integrity in relational databases ensures that every table has a primary key, which is both unique and non-null, guaranteeing that each record is distinct and identifiable.
This concept is crucial for maintaining consistent and accurate relationships between tables, as it prevents ambiguities and errors in data retrieval and manipulation.
In entity integrity, the primary key attribute identifies each entity in a table.
Domain Integrity
Domain Integrity in relational databases refers to a set of constraints that enforce valid entries for a given column by restricting the type, format, and range of possible values.
This ensures that data entered into a database adheres to defined rules, such as permissible value ranges, correct data types, and specific formats, thereby maintaining accuracy and consistency of the data within each field.
Domain integrity defines the values that can be stored in a particular column in a database table.
Referential Integrity
Referential Integrity is a key concept in relational databases that ensures relationships between tables remain consistent, specifically by ensuring that a foreign key in one table always refers to an existing and valid primary key in another table.
This integrity constraint prevents the creation of orphaned records and maintains the accuracy and consistency of data across different tables within the database.
Referential integrity ensures that key values in a database always match a primary key value in another table.
Orphaned Records
Orphaned records are entries in a child table that do not have corresponding entries in the parent table, usually due to the deletion or modification of related records in the parent table.
These records have foreign key values pointing to non-existent primary keys, leading to broken references and inconsistencies in the database.
Orphaned Record
Cascade Delete
Cascade Delete is a referential integrity constraint in a relational database that automatically deletes all related records in child tables when a record in the parent table is deleted.
This action ensures that there are no orphaned records in the child tables, maintaining referential integrity and preventing data inconsistencies.
Cascade delete is a feature that automatically all related records when a parent record is deleted.
Redundant Data
Redundant data is data that is duplicated or unnecessarily repeated within a database. This can occur in various forms, such as storing the same information in multiple tables or keeping multiple copies of the same record.
Redundancy often leads to increased storage requirements and can result in inconsistencies, where one instance of the data is updated but others are not, leading to data integrity issues.
While some redundancy might be intentional for performance or backup purposes, excessive or unmanaged redundancy is generally undesirable.
In database systems, redundant data refers to the of data.
