Table of contents
Data Integrity:
Definition: Data integrity refers to the accuracy, consistency, and reliability of data stored in a database over its entire lifecycle.
Importance of Data Integrity:
Ensures the reliability and trustworthiness of data.
Guarantees that data meets certain standards and constraints.
Prevents data corruption, loss, or unauthorized modifications.
Types of Data Integrity:
Entity Integrity: Ensures that each row in a table is uniquely identified by a primary key and that the primary key column does not contain null values.
Referential Integrity: Maintains the consistency between related tables by enforcing relationships and preventing orphaned or inconsistent data.
Domain Integrity: Ensures that data within a column adheres to specified data types, formats, ranges, or constraints.
User-defined Integrity: Additional integrity rules defined by users or application requirements.
Techniques for Enforcing Data Integrity:
Primary Keys: Establishes a unique identifier for each row in a table.
Foreign Keys: Defines relationships between tables and ensures referential integrity.
Check Constraints: Defines specific conditions that data must meet to maintain integrity.
Data Validation: Verifies the accuracy and integrity of data before it is entered into the database.
Triggers: Automatically executes actions or validations based on specified events or conditions.
Constraints:
Definition: Constraints are rules or conditions that are applied to the data in a database to enforce integrity, consistency, and validity.
Common Types of Constraints:
Primary Key Constraint: Ensures that the primary key column(s) contain unique and non-null values.
Foreign Key Constraint: Enforces referential integrity by ensuring that values in a column match values in a related table's primary key.
Unique Constraint: Ensures that the values in a column or a combination of columns are unique.
Check Constraint: Validates that data meets specific conditions or expressions.
Not Null Constraint: Requires a column to contain a non-null value.
Default Constraint: Specifies a default value for a column when no value is provided during insertion.
Purpose of Constraints:
Maintain data integrity and consistency.
Prevent invalid or inconsistent data from being inserted, updated, or deleted.
Enforce business rules and data validation requirements.
Improve data quality and reliability.
Benefits of Constraints:
Promote data integrity and accuracy.
Improve data consistency and reliability.
Simplify application logic by offloading data validation to the database.
Enhance data protection and security.
Provide better error handling and error reporting.