1) What is the difference between ON DELETE SET NULL clause and ON DELETE CASCADE clause in ORACLE.
ON DELETE SET NULL:
drop table students;
create table Students
(
id int,
name varchar(10),
dept_id int constraint c1 primary key);
insert into students values(1,'vishnu',11);
insert into students values(2,'vinay',12);
insert into students values(3,'Teja',13);
insert into students values(4,'Ashwin',14);
drop table dept;
create table dept
(
dept_id int constraint c2 references students(dept_id) on delete set null,
dept_name...
