Question

考虑来自#myTempTwo的以下数据样本

sno     |   name        |budget |NameTrim   |TravelCost|    Expense
1       |Local Travel   |123    |Travel     |246       |    NULL
2       |Global Travel  |123    |Travel     |246       |    NULL
3       |Local Expense  |12     |Expense    |NULL      |    24
4       |Curent Expense |12     |Expense    |NULL      |    24

使用值TravelCost或Expense为null更新的情况。让我们说费用为1，旅行费用为2。

现在说更新：

update #myTempTwo 
 set TravelCost = '2' where TravelCost is null
 update #myTempTwo 
 set Expense = '1' where Expense is null

这将产生：

    sno     |   name        |budget |NameTrim   |TravelCost|    Expense
    1       |Local Travel   |123    |Travel     |246       |    1
    2       |Global Travel  |123    |Travel     |246       |    1
    3       |Local Expense  |12     |Expense    |2         |    24
    4       |Curent Expense |12     |Expense    |2         |    24

我可以以某种方式查看原始数据（在运行更新之前，而不将其保存在其他表中。我正在寻找一些＆＃39;撤消＆＃39;或者查看历史记录＆＃39 ;或某些临时快照＆＃39;？（使用sql server 2012）

如果是，我该怎么做？

Answer 1

以下是触发器和历史记录表的示例：

CREATE TABLE OriginaTable(ID INT IDENTITY, Price MONEY)
GO

CREATE TABLE HistoryTable(ID INT IDENTITY, OriginalID INT, Price MONEY, CreatedDate DATETIME)
GO

CREATE TRIGGER trOriginaTable ON OriginaTable
FOR UPDATE
AS
BEGIN
  IF UPDATE(Price)
  BEGIN
        INSERT INTO dbo.HistoryTable
                ( OriginalID, Price, CreatedDate )
                SELECT ID, Price, GETDATE() FROM Deleted
  END
END
GO

INSERT INTO OriginaTable VALUES(NULL)
GO

UPDATE dbo.OriginaTable SET Price = 100 WHERE ID = 1
UPDATE dbo.OriginaTable SET Price = 10 WHERE ID = 1
UPDATE dbo.OriginaTable SET Price = 200 WHERE ID = 1

SELECT * FROM dbo.HistoryTable

输出：

ID  OriginalID  Price   CreatedDate
1   1           NULL    2015-11-05 18:46:49.823
2   1           100.00  2015-11-05 18:46:49.830
3   1           10.00   2015-11-05 18:46:49.833

如您所见，历史记录会保存所有旧值。

SQL Server - 更新表历史记录

1 个答案: