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SQL>
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> CREATE TABLE major_stats (
2 major VARCHAR2(30),
3 total_credits NUMBER,
4 total_lecturer NUMBER);
Table created.
SQL>
SQL>
SQL> CREATE OR REPLACE TRIGGER myTrigger
2 AFTER INSERT OR DELETE OR UPDATE ON lecturer
3 DECLARE
4 CURSOR c_Statistics IS
5 SELECT major, COUNT(*) total_lecturer,
6 SUM(current_credits) total_credits
7 FROM lecturer
8 GROUP BY major;
9 BEGIN
10 FOR v_StatsRecord in c_Statistics LOOP
11 UPDATE major_stats
12 SET total_credits = v_StatsRecord.total_credits,
13 total_lecturer = v_StatsRecord.total_lecturer
14 WHERE major = v_StatsRecord.major;
15 IF SQL%NOTFOUND THEN
16 INSERT INTO major_stats (major, total_credits, total_lecturer)
17 VALUES (v_StatsRecord.major, v_StatsRecord.total_credits,
18 v_StatsRecord.total_lecturer);
19 END IF;
20 END LOOP;
21 END myTrigger;
22 /
Trigger created.
SQL>
SQL> drop table major_stats;
Table dropped.
SQL> drop table lecturer;
Table dropped.
SQL>
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