The assurance that information can only be accessed or modified by those authorized to do so. Data integrity can be maintained by the DBMS or maintained by the software application. Therefore, data integrity can be implemented inside the database and through data access rules. Data integrity includes the following:
- Entity integrity keeps duplicate records from being inserted in a table and is enforced through primary keys and normalized database designs.
- Domain integrity means that only valid values are entered into a field. It is enforced through foreign key constraints, column-level rules, or lookup tables.
- Referential integrity makes sure that no foreign keys point to records that do not exist. It is enforced using foreign key constraints.
- Business rules integrity applies additional rules to data as it specifically relates to the business. These rules may cross column, row, and even table or database boundaries.