If a foreign key is set up between two tables it may be that
you cannot insert unless a related record exists. In this example
we cannot add ('Tom', 'ma') to t_staff table unless we first
create a maths department ('ma', 'Mathematics') in the t_dept table.
CREATE TABLE t_dept( id CHAR(2) ,fname VARCHAR(20) ,PRIMARY KEY(id)); CREATE TABLE t_staff( name VARCHAR(20) ,dept CHAR(2) ,PRIMARY KEY(name) ,FOREIGN KEY(dept) REFERENCES t_dept(id))
|Specific to Oracle|
|We can examine this constraint to find the table that has it...|