A vital aspect of a database is data integrity. Data integrity means that the data in the database is complete and consistent both at its creation and at all times during use. Taking into account that a database is a resource shared by many applications, it is advisable to register any knowledge about data semantics in the database in such a way that there is no need to replicate it into the applications using such knowledge.
Types of integrity constraints
Entity integrity
Domain integrity
Referential integrity