How to remove foreign key from table?

Question

i want a query from which i will remove foreign key from the table. plz help me in it. the table is created as follows:
CREATE TABLE cw06_course
     (coursecode NUMBER(4) CONSTRAINT coursecode_pk PRIMARY KEY,
     department NUMBER(4) CONSTRAINT course_department_nn NOT NULL,
     coursename VARCHAR2(25),
     courseleasder NUMBER(4),
     CONSTRAINT course_department_fk FOREIGN KEY (department) REFERENCES cw06_department(deptno));

Answer 1

parent keys not foundWell, while the constraint was not available (dropped), someone took the opportunity and inserted rows into your child table that do not have a corresponding value in your parent table.
Why was the constraint dropped in first place? why did you give someone the opportunity to insert constraint violating value into the table?
You must either:
1). remove the child rows not found in parent
2). create parent rows fr missing child rows.
3). enable novalidate the constraint so existing values can remain without parent but future rows must confirm.