PRAGMA foreign_keys = ON;
 
CREATE TABLE AUTHOR (
AUTHOR_ID NUMBER(5) PRIMARY KEY,
AUTHOR_NAME VARCHAR2(18)
);
 
INSERT INTO AUTHOR (AUTHOR_ID, AUTHOR_NAME) VALUES (1234, 'MC GRAW HILL');
INSERT INTO AUTHOR (AUTHOR_ID, AUTHOR_NAME) VALUES (1235, 'J K ROLLING');    
INSERT INTO AUTHOR (AUTHOR_ID, AUTHOR_NAME) VALUES (1236, 'WILLAM');
INSERT INTO AUTHOR (AUTHOR_ID, AUTHOR_NAME) VALUES (1237, 'SHAKESPEAR');
 
CREATE TABLE BOOK 
(
BOOK_ID NUMBER(5) PRIMARY KEY,
BOOK_NAME VARCHAR2(15),
AUTHOR_ID NUMBER(5),
CONSTRAINT author_fk
FOREIGN KEY (AUTHOR_ID) REFERENCES AUTHOR(AUTHOR_ID)
ON DELETE CASCADE
);
 
INSERT INTO BOOK (BOOK_ID, BOOK_NAME, AUTHOR_ID) 
    VALUES (10001, 'SOFTWARE DEVELOPEMENT', 1234);
INSERT INTO BOOK (BOOK_ID, BOOK_NAME, AUTHOR_ID) 
    VALUES (10002, 'HARRY POTTER', 1235);
INSERT INTO BOOK (BOOK_ID, BOOK_NAME, AUTHOR_ID) 
    VALUES (10003, 'TO BE OR NOT TO BE', 1237);
INSERT INTO BOOK (BOOK_ID, BOOK_NAME, AUTHOR_ID) 
    VALUES (10004, 'PROJECT MANAGEMENT', 1234);
 
DELETE FROM AUTHOR WHERE AUTHOR_ID = 1234;
 
Select * from book ;
 
Select * from author ;

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