Cascade inserts into myStudent into session and lecturer.

   
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 session (
  2    department       CHAR(3),
  3    course           NUMBER(3),
  4    description      VARCHAR2(2000),
  5    max_lecturer     NUMBER(3),
  6    current_lecturer NUMBER(3),
  7    num_credits      NUMBER(1),
  8    room_id          NUMBER(5)
  9    );

Table created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('HIS', 101, 'History 101', 30, 11, 4, 20000);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('HIS', 301, 'History 301', 30, 0, 4, 20004);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('CS', 101, 'Computer Science 101', 50, 0, 4, 20001);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('ECN', 203, 'Economics 203', 15, 0, 3, 20002);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('CS', 102, 'Computer Science 102', 35, 3, 4, 20003);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('MUS', 410, 'Music 410', 5, 4, 3, 20005);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('ECN', 101, 'Economics 101', 50, 0, 4, 20007);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('NUT', 307, 'Nutrition 307', 20, 2, 4, 20008);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('MUS', 100, 'Music 100', 100, 0, 3, NULL);

1 row created.

SQL>
SQL>
SQL> CREATE TABLE myStudent (
  2    student_id NUMBER(5) NOT NULL,
  3    department CHAR(3)   NOT NULL,
  4    course     NUMBER(3) NOT NULL,
  5    grade      CHAR(1)
  6    );

Table created.

SQL>
SQL> CREATE OR REPLACE TRIGGER myTrigger
  2    BEFORE INSERT ON myStudent
  3    FOR EACH ROW
  4  DECLARE
  5    v_Credits session.num_credits%TYPE;
  6  BEGIN
  7    SELECT num_credits
  8      INTO v_Credits
  9      FROM session
 10      WHERE department = :new.department
 11      AND course = :new.course;
 12
 13    UPDATE lecturer
 14      SET current_credits = current_credits + v_Credits
 15      WHERE ID = :new.student_id;
 16
 17    UPDATE session
 18      SET current_lecturer = current_lecturer + 1
 19      WHERE department = :new.department
 20      AND course = :new.course;
 21  END myTrigger;
 22  /

Trigger created.

SQL>
SQL>
SQL>
SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10000, 'CS', 102, 'A');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10002, 'CS', 102, 'B');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10003, 'CS', 102, 'C');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10000, 'HIS', 101, 'A');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10001, 'HIS', 101, 'B');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10002, 'HIS', 101, 'B');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10003, 'HIS', 101, 'A');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10004, 'HIS', 101, 'C');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10005, 'HIS', 101, 'C');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10006, 'HIS', 101, 'E');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10007, 'HIS', 101, 'B');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10008, 'HIS', 101, 'A');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10009, 'HIS', 101, 'D');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10010, 'HIS', 101, 'A');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10008, 'NUT', 307, 'A');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10010, 'NUT', 307, 'A');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10009, 'MUS', 410, 'B');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10006, 'MUS', 410, 'E');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10011, 'MUS', 410, 'B');

1 row created.

SQL>
SQL> INSERT INTO myStudent (student_id, department, course, grade)
  2                           VALUES (10000, 'MUS', 410, 'B');

1 row created.

SQL> drop table session;

Table dropped.

SQL>
SQL> drop table lecturer;

Table dropped.

SQL>
SQL> drop table myStudent;

Table dropped.
Related examples in the same category

1.	create or replace trigger
2.	Oracle's syntax for creating a trigger based on two tables
3.	Trigger on each row
4.	Use Sequence in a trigger
5.	Empty trigger(before insert or update or delete)
6.	Create tigger on wrapper table
7.	This trigger sends messages over a pipe to record inserts into myStudent.
8.	Trigger is autonomous and hence the changes will be logged even if the original transaction rolls back.
9.	Trigger Which Modifies a Mutating Table
10.	Creating a Trigger with cursor inside
11.	Autonumbering Trigger
12.	Use RAISE_APPLICATION_ERROR in a trigger
13.	Show errors for a trigger
14.	Submit job from a trigger
15.	Use sysdate and user function in a trigger
Cascade inserts into myStudent into session and lecturer. : Create Trigger « Trigger « Oracle PL / SQL

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