In the school example, the primary key used to identify each member of staff in the teacher table is Staff ID. A foreign key is a primary key from one table that appears in another table to link ...

The third sub-language in SQL declares queries, through the SELECT statement and relational ... Orders ( OrderID int NOT NULL PRIMARY KEY, ... PersonID int FOREIGN KEY REFERENCES Persons(PersonID ...

Cascading referential integrity constraints are foreign key constraints that tell SQL Server to ... be set to NULL when the primary key record is deleted. If an update statement affects rows ...