Eine Einführung in

SQL

Cannot DELETE because of reference.

Oracle
If a foreign key is set up between two tables it may be that you cannot delete a record. In this case the table t_staff references the table t_dept - you cannot delete the department 'co' if a member of staff belongs to that department.
Execute set up code


Specific to Oracle
We can examine this constraint to find the table that has it...
SELECT constraint_name, table_name, status
FROM user_constraints
WHERE r_constraint_name IN (
     SELECT constraint_name
     FROM user_constraints
     WHERE table_name ='T_DEPT')