將新值輸入到特定列時的操作

Question

我有一個數據庫表，它具有通過從日誌文件導入插入的新記錄。我想寫一個作業，當一個特定的新字段被輸入時發送一個警報。到目前爲止，我一直在檢查該字段中唯一條目的數量，當它增加設置值時，我會收到警報。問題是每次我需要返回並更新查詢中的計數。所以只是想知道是否有另一種方式來做到這一點。

Declare @count as int 
select @count = count(clientkey) from QueryData group by clientkey 
If @@ROWCOUNT > 18 

EXEC msdb.dbo.sp_send_dbmail @profile_name='DB Admin', 
    @recipients = 'joe@mail.com', 
    @copy_recipients = 'pete@mail.com', 
    @subject = 'GPDB Warning', 
    @body = 'A new clientkey is being used in the QueryData table' 

欣賞任何響應

編輯：

表

CREATE TABLE [dbo].[QueryData](
[ImportDate] [datetime] NULL, 
[clientKey] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, 
[QueryTerms] [nvarchar](max) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, 
[UpdatedDate] [datetime] NULL, 
[LastSearchDate] [datetime] NULL, 
[QueryActivity] AS (datediff(day,[UpdatedDate],[LastSearchDate])) PERSISTED, 
[ImportMethod] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, 
[PowerField] [nvarchar](5) COLLATE SQL_Latin1_General_CP1_CI_AS NULL 
) ON [PRIMARY] 

所以當發生進口importdate被更新，updatedDate場也被更新。客戶端密鑰字段是我關心的一個，客戶端密鑰可以有多行，但我需要知道何時插入了一個尚未插入的新密鑰。

Answer 1

你可以用這個來代替觸發器。唯一複雜的是，你必須重複INSERT ...

CREATE TRIGGER dbo.QueryData_NewClientKey 
ON dbo.QueryData 
INSTEAD OF INSERT 
AS 
BEGIN 
    IF EXISTS (SELECT 1 FROM inserted AS i 
    LEFT OUTER JOIN dbo.QueryData AS q 
    ON i.clientkey = q.clientkey 
    WHERE q.clientkey IS NULL 
) 
    BEGIN 
    -- send your e-mail here 
    END 

    INSERT dbo.QueryData(column1, columns2, etc.) 
    SELECT column1, column2, etc. FROM inserted; 
END 
GO 

隨着扳機後，你需要有能力，你只需插入到表之前存在的行和列進行區分，所以邏輯稍微複雜一些。假設你在桌面上有一個主鍵，你可以說：

CREATE TRIGGER dbo.QueryData_NewClientKey 
ON dbo.QueryData 
FOR INSERT 
AS 
BEGIN 
    IF EXISTS (SELECT 1 FROM dbo.QueryData AS new_data 
    INNER JOIN inserted AS i 
    ON new_data.key = i.key 
    LEFT OUTER JOIN dbo.QueryData AS old_data 
    ON i.clientkey = old_data.clientkey 
    AND i.key <> old_data.key 
    WHERE old_data.key IS NULL 
) 
    BEGIN 
    -- send your e-mail 
    END 
END 
GO