#integrity constraints in sql

[bigdatansql]

Entity Integrity

Entity Integrity ensures that the table contains no duplicate records and that the field that identifies each entry is distinct and never null. The Primary Key's presence is critical to the entity's integrity. If a primary key is defined for each entity,

Entity Integrity ensures that the table contains no duplicate records and that the field that identifies each entry is distinct and never null. The Primary Key’s presence is critical to the entity’s integrity. If a primary key is defined for each entity, the entity integrity rule is followed. In other words, entity integrity requires that the Primary Keys on each instance of an entity be…

View On WordPress