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DROP TABLE IF EXISTS employees CASCADE;
CREATE TABLE employees (
fname varchar(255),
minit varchar(1),
lname varchar(255),
sin varchar(9) primary key,
bdate date,
address varchar(255),
gender varchar(1),
salary integer,
dno integer
);
DROP TABLE IF EXISTS departments CASCADE;
CREATE TABLE departments (
dname varchar(255),
dnumber integer primary key,
mgrsin varchar(9),
mgrstartdate date
);
DROP TABLE IF EXISTS projects CASCADE;
CREATE TABLE projects (
pname varchar(255),
pnumber integer primary key,
plocation varchar(255),
dnum integer
);
DROP TABLE IF EXISTS locations CASCADE;
CREATE TABLE locations (
dnbr integer,
dlocation varchar(255)
);
INSERT INTO employees VALUES ('Harris', 'T', 'Chomsky', 123, '1965-12-10', 'Edmonton', 'M', 50000, 12);
INSERT INTO employees VALUES ('Kristian', 'C', 'Bohr' , 456, '1975-10-05', 'Ottawa', 'M', 28000, 11);
INSERT INTO employees VALUES ('Charlotte', 'F', 'Bouchard' , 789, '1985-08-06', 'Montreal', 'F', 40000, 11);
INSERT INTO employees VALUES ('Said', 'J', 'Ahmad', 111, '1970-09-07', 'Toronto', 'M', 30000, 12);
INSERT INTO employees VALUES ('Andrew', 'U', 'Brahe', 222, '1970-04-02', 'Winnipeg', 'M', 20000, 10);
INSERT INTO employees VALUES ('Nadia', 'O', 'Mamary', 333, '1960-01-08', 'Saskatoon', 'F', 35000, 10);
INSERT INTO employees VALUES ('Yuan', 'P', 'Nielsen', 987, '1983-02-27', 'Moncton', 'F', 32000, 11);
INSERT INTO employees VALUES ('Neil', 'A', 'Dion', 654, '1953-02-27', 'Moncton', 'M', 32000, 11);
INSERT INTO employees VALUES ('Karen', 'C', 'Ming', 321, '1963-11-16', 'Victoria', 'F', 26000, 12);
INSERT INTO departments VALUES ('ConsProd', 10, 333, '2004-10-01');
INSERT INTO departments VALUES ('InduProd', 11, 654, '2005-05-01');
INSERT INTO departments VALUES ('Research', 12, 111, '2000-06-15');
INSERT INTO projects VALUES ('Mobile University', 1, 'Ottawa', 10);
INSERT INTO projects VALUES ('Interactive TV', 2, 'Ottawa', 12);
INSERT INTO projects VALUES ('Intelligent Agent', 3, 'Athabasca', 11);
INSERT INTO projects VALUES ('E-Commerce', 4, 'Edmonton', 10);
INSERT INTO projects VALUES ('Mobile Office', 5, 'Athabasca', 11);
INSERT INTO locations VALUES (10, 'Edmonton');
INSERT INTO locations VALUES (10, 'Ottawa');
INSERT INTO locations VALUES (11, 'Athabasca');
INSERT INTO locations VALUES (12, 'Ottawa');
INSERT INTO locations VALUES (12, 'Montreal');
-- ALTER TABLE departments ADD CONSTRAINT employees_fk FOREIGN KEY (mgrsin) REFERENCES employees (sin);
-- ALTER TABLE employees ADD CONSTRAINT departments_fk FOREIGN KEY (dno) REFERENCES departments (dnumber);
-- ALTER TABLE locations ADD CONSTRAINT departments_fk FOREIGN KEY (dnbr) REFERENCES departments(dnumber);
-- ALTER TABLE projects ADD CONSTRAINT departments_fk FOREIGN KEY (dnum) REFERENCES departments (dnumber);
CREATE OR REPLACE FUNCTION update_referenced_department_numbers() RETURNS trigger AS $$
BEGIN
IF NEW.dnumber <> OLD.dnumber THEN
UPDATE employees SET dno = NEW.dnumber WHERE dno = OLD.dnumber;
UPDATE locations SET dnbr = NEW.dnumber WHERE dnbr = OLD.dnumber;
UPDATE projects SET dnum = NEW.dnumber WHERE dnum = OLD.dnumber;
END IF;
RETURN NEW;
END
$$ LANGUAGE plpgsql;
DROP TRIGGER IF EXISTS update_department_number on departments CASCADE;
CREATE TRIGGER update_department_number AFTER UPDATE
ON departments
FOR EACH ROW
WHEN (OLD.dnumber <> NEW.dnumber)
EXECUTE PROCEDURE update_referenced_department_numbers();
CREATE OR REPLACE FUNCTION update_referenced_sin_numbers() RETURNS trigger AS $$
BEGIN
IF NEW.sin <> OLD.sin THEN
UPDATE departments set mgrsin = NEW.sin WHERE mgrsin = OLD.sin;
END IF;
RETURN NEW;
END
$$ LANGUAGE plpgsql;
DROP TRIGGER IF EXISTS update_sin ON employees CASCADE;
CREATE TRIGGER update_sin AFTER UPDATE
ON employees
FOR EACH ROW
WHEN (OLD.sin <> NEW.sin)
EXECUTE PROCEDURE update_referenced_sin_numbers();
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