Database_Triggers_Project/script.sql at main · Sandhya80/Database_Triggers_Project · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92


-- task 1:
SELECT * FROM customers
ORDER BY customer_id;

SELECT * FROM customers_log;

-- UPDATE TRIGGERS:
-- task 2:
CREATE TRIGGER customer_updated
BEFORE UPDATE ON customers
FOR EACH ROW
EXECUTE PROCEDURE log_customers_change();

-- task 3:
UPDATE customers
SET first_name = 'Steve'
WHERE last_name = 'Hall';

SELECT * FROM customers
ORDER BY customer_id;

SELECT * FROM customers_log;

-- task 4:
UPDATE customers
SET years_old = 10
WHERE last_name = 'Hall';

SELECT * FROM customers
ORDER BY customer_id;

SELECT * FROM customers_log;

-- INSERT TRIGGERS:
-- task 5:
CREATE TRIGGER customer_insert
AFTER INSERT ON customers
FOR EACH STATEMENT
EXECUTE PROCEDURE log_customers_change();

-- task 6:
INSERT INTO customers (first_name, last_name, years_old)
VALUES
('Jeffrey', 'Cook', 66),
('Arthur', 'Turner', 49),
('Nathan', 'Cooper', 72);

SELECT * FROM customers
ORDER BY customer_id;

SELECT * FROM customers_log;

-- CONDITIONALS ON YOUR TRIGGERS:
-- task 7:
CREATE TRIGGER customer_min_age
BEFORE UPDATE ON customers
FOR EACH ROW
WHEN (NEW.years_old < 13)
EXECUTE PROCEDURE override_with_min_age();

-- task 8:
UPDATE customers
SET years_old = 12
WHERE last_name = 'Campbell';

UPDATE customers
SET years_old = 24
WHERE last_name = 'Cook';

SELECT * FROM customers
ORDER BY customer_id;

SELECT * FROM customers_log;

-- task 9:
UPDATE customers
SET years_old = 9, first_name = 'Dennis'
WHERE last_name = 'Hall';

SELECT * FROM customers
ORDER BY customer_id;

SELECT * FROM customers_log;

-- task 10:
DROP TRIGGER IF EXISTS customer_min_age
ON customers;

-- task 11:
SELECT * FROM information_schema.triggers;