3-mavzu: sql – delete va update instruksiyasi. Reja

3-MAVZU: SQL – DELETE VA UPDATE INSTRUKSIYASI.
REJA:
1. SQL tilida delete?
2. SQL tili funksiyalari?
3. SQL tilida update funksiyasi?
Tayanch so‘z va iboralar. SQL, SQL tili, ALTER,delete, update, structured query language, mbbt, "klient-server" oracle, interаktiv, ddl, dml, dcd, select. va h.k.
SQL-da jadval yaratish va to'ldirishdan so'ng, UPDATE buyruq ustun qiymatini o'zgartirish uchun ishlatilishi mumkin. Agar yo'q bo'lsa WHERE, u jadvaldagi barcha qatorlarning qiymatini o'zgartiradi, shuning uchun uning yangilanishini to'g'ri WHERE shart bilan cheklaganingizga ishonch hosil qiling.
Buyruq DELETE qatorlarni o'chirish uchun ishlatilishi mumkin. Xuddi shunday, agar yo'q WHERE belgilanmagan bo'lsa, u barcha qatorlarni o'chirib tashlaydi, shuning uchun uni cheklaganingizga ishonch hosil qiling.

CREATE TABLE inventory (id INTEGER PRIMARY KEY, item TEXT, price REAL);

INSERT INTO inventory VALUES (1, "Santa Hat", 20.00);
INSERT INTO inventory VALUES (2, "Reindeer nose", 5.00);
INSERT INTO inventory VALUES (3, "Elf hat", 10.00);
INSERT INTO inventory VALUES (4, "Witches hat", 30.00);
SELECT * FROM inventory;
UPDATE inventory SET price = 20.00 WHERE id = 4;
SELECT * FROM inventory;
DELETE FROM inventory WHERE id = 4;
SELECT * FROM inventory;
MA’LUMOTLAR BAZASI SXEMASI

inventory 3 rows
id (PK)	INTEGER
item	TEXT
price	REAL

SOʻROV NATIJALARI