Лекція 7. Транзакції

Приклади.

1.Одна транзакція

BEGIN TRANSACTION

USE pubs

GO

UPDATE titles

SET advance = advance * 1.25

WHERE ytd_sales > 8000

GO

COMMIT

GO

2. Вкладені транзакції

CREATE TABLE TestTran (Cola INT PRIMARY KEY, Colb CHAR(3))

GO

BEGIN TRANSACTION OuterTran -- @@TRANCOUNT set to 1.

GO

INSERT INTO TestTran VALUES (1, 'aaa')

GO

BEGIN TRANSACTION Inner1 -- @@TRANCOUNT set to 2.

GO

INSERT INTO TestTran VALUES (2, 'bbb')

GO

BEGIN TRANSACTION Inner2 -- @@TRANCOUNT set to 3.

GO

INSERT INTO TestTran VALUES (3, 'ccc')

GO

COMMIT TRANSACTION Inner2 -- Decrements @@TRANCOUNT to 2.

-- Nothing committed.

GO

COMMIT TRANSACTION Inner1 -- Decrements @@TRANCOUNT to 1.

-- Nothing committed.

GO

COMMIT TRANSACTION OuterTran -- Decrements @@TRANCOUNT to 0.

-- Commits outer transaction OuterTran.

GO