Mega Code Archive

These triggers demonstrate the use of the

SQL> SQL> CREATE TABLE lecturer ( 2 id NUMBER(5) PRIMARY KEY, 3 first_name VARCHAR2(20), 4 last_name VARCHAR2(20), 5 major VARCHAR2(30), 6 current_credits NUMBER(3) 7 ); Table created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10001, 'Scott', 'Lawson','Computer Science', 11); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major, current_credits) 2 VALUES (10002, 'Mar', 'Wells','History', 4); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10003, 'Jone', 'Bliss','Computer Science', 8); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10004, 'Man', 'Kyte','Economics', 8); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10005, 'Pat', 'Poll','History', 4); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10006, 'Tim', 'Viper','History', 4); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10007, 'Barbara', 'Blues','Economics', 7); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10008, 'David', 'Large','Music', 4); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10009, 'Chris', 'Elegant','Nutrition', 8); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10010, 'Rose', 'Bond','Music', 7); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10011, 'Rita', 'Johnson','Nutrition', 8); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10012, 'Sharon', 'Clear','Computer Science', 3); 1 row created. SQL> SQL> SQL> CREATE OR REPLACE TRIGGER GenerateStudentID 2 BEFORE INSERT OR UPDATE ON lecturer 3 FOR EACH ROW 4 BEGIN 5 SELECT 20001 6 INTO :new.ID 7 FROM dual; 8 END GenerateStudentID; 9 / Trigger created. SQL> SQL> INSERT INTO lecturer (first_name, last_name) 2 VALUES ('L', 'L'); 1 row created. SQL> SQL> SQL> SQL> select * from lecturer; ID FIRST_NAME LAST_NAME ---------- -------------------- -------------------- MAJOR CURRENT_CREDITS ------------------------------ --------------- 10001 Scott Lawson Computer Science 11 10002 Mar Wells History 4 10003 Jone Bliss Computer Science 8 ID FIRST_NAME LAST_NAME ---------- -------------------- -------------------- MAJOR CURRENT_CREDITS ------------------------------ --------------- 10004 Man Kyte Economics 8 10005 Pat Poll History 4 10006 Tim Viper History 4 ID FIRST_NAME LAST_NAME ---------- -------------------- -------------------- MAJOR CURRENT_CREDITS ------------------------------ --------------- 10007 Barbara Blues Economics 7 10008 David Large Music 4 10009 Chris Elegant Nutrition 8 ID FIRST_NAME LAST_NAME ---------- -------------------- -------------------- MAJOR CURRENT_CREDITS ------------------------------ --------------- 10010 Rose Bond Music 7 10011 Rita Johnson Nutrition 8 10012 Sharon Clear Computer Science 3 ID FIRST_NAME LAST_NAME ---------- -------------------- -------------------- MAJOR CURRENT_CREDITS ------------------------------ --------------- 20001 L L 13 rows selected. SQL> SQL> drop table lecturer; Table dropped.