Question: SQL allows a foreign key dependency to refer to the same

SQL allows a foreign-key dependency to refer to the same relation, as in the following example: create table manager (employee-name char (20), manager-name char(20), primary key employee-name, foreign key (manager-name) references manager on delete cascade ) Here, employee-name is a key to the table manager, meaning that each employee has at most one manager. The foreign-key clause requires that every manager also be an employee. Explain exactly what happens when a tuple in the relation manager is deleted.

View Solution:


Sale on SolutionInn
Sales0
Views220
Comments
  • CreatedJanuary 28, 2011
  • Files Included
Post your question
5000