Mavzu: sql da funksiyalar va triggerlar yaratish

Mavzu: sql da funksiyalar va triggerlar yaratish

Omonov Abbosxon 612-20 guruh talabasui.

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Mavzu: SQL da funksiyalar va triggerlar yaratish.

Ishdan maqsad: SQL da triggerlarr va funksiyalar yaratish bo`yicha ko`nikmaga ega bo`lish.
Masalaning qo`yilishi: Berilgan predmet soha ma`lumotlar bazasidagi barcha ob`yektlarni ustida funsiyalar va triggerlar yaratish asosida amallarini bajarish.
Uslubiy ko`rsatmalar:
Triggerlar - bu to'g'ridan-to'g'ri chaqirilmaydigan, ammo ma'lum bir voqea sodir bo'lganda bajariladigan (qatorni qo'shish, o'chirish, yangilash) saqlanadigan protsedura.
Funksiyalar (FUNCTION) - protseduraga o'xshash, bu biz qayta-qayta ishlatmoqchi bo'lgan ba'zi SQL kod. Funktsiya va protsedura o'rtasidagi farq shundan iboratki, funktsiya faqat bitta parametrni qaytaradi va funktsiya "Call" qilmasdan nomi bilan chaqiriladi

FUNCTIONS

1. 
   
   Minus
   

mysql> create function minus(a int, b int)

-> returns int
-> deterministic
-> begin

-> declare result int;

-> set result = a - b;
-> return (result);
-> end//

Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;
mysql> select minus(100, 25);
+----------------+
| minus(100, 25) |
+----------------+
| 75 |

+----------------+

1 row in set (0.00 sec)

mysql>

2. 
   
   Bo`lish
   

mysql> create function bolish(a float, b float)

-> returns float
-> deterministic
-> begin

-> declare result float;

-> set result = a / b;
-> return (result);
-> end//

Query OK, 0 rows affected (0.00 sec)

mysql> select bolish(10, 3)//
+------------------+
| bolish(10, 3) |
+------------------+
| 3.33333325386047 |
+------------------+
1 row in set (0.06 sec)
mysql>

3. 
   
   Ildiz
   

mysql> create function ildiz(a float)

-> returns float
-> deterministic
-> begin

-> declare result float;

-> set result = sqrt(a);
-> return (result);
-> end//

Query OK, 0 rows affected (0.07 sec)

mysql> select ildiz(16)//
+-----------+
| ildiz(16) |
+-----------+
| 4 |
+-----------+

1 row in set (0.00 sec)

mysql>

4. 
   
   Modul
   

mysql> create function modul(a int)

-> returns int
-> deterministic
-> begin

-> declare result int;

-> set result = abs(a);
-> return (result);
-> end//

Query OK, 0 rows affected (0.00 sec)

mysql> select modul(-1)//
+-----------+
| modul(-1) |
+-----------+
| 1 |
+-----------+

1 row in set (0.00 sec)

mysql>

5.