爲什麼有外鍵衝突

這裏是主表：爲什麼有外鍵衝突

CREATE TABLE [dbo].[Control_cReport](
    [ReportKey] [int] IDENTITY(10000,1) NOT NULL, 
    [ReportTechKey] [int] NOT NULL, 
    [ProcessKey] [int] NULL, 
CONSTRAINT [PK_Control_cReport] PRIMARY KEY CLUSTERED 
(
    [ReportKey] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 

GO 

ALTER TABLE [dbo].[Control_cReport] WITH CHECK ADD CONSTRAINT [FK_Control_cReport_cReportTech] FOREIGN KEY([ReportTechKey]) 
REFERENCES [dbo].[Control_cReportTech] ([ReportTechKey]) 
GO 

ALTER TABLE [dbo].[Control_cReport] CHECK CONSTRAINT [FK_Control_cReport_cReportTech] 
GO 

ALTER TABLE [dbo].[Control_cReport] ADD DEFAULT ((12)) FOR [ProcessKey] 
GO

這裏是二手錶：

CREATE TABLE [dbo].[Control_cReportTech](
    [ReportTechKey] [int] NOT NULL, 
    [ReportTechDescription] [nvarchar](50) NOT NULL, 
CONSTRAINT [PK__Control_cReportTech] PRIMARY KEY CLUSTERED 
(
    [ReportTechKey] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 

GO

，我已經加入到二次表：

INSERT INTO [WHAnalysis].[dbo].Control_cReportTech 
VALUES 
    (1,'Excel Macros'), 
    (2,'VB Script'), 
    (3,'PDF'), 
    (4,'Batch')

現在我正在嘗試INSERT一些舊數據表的數據通過以下方式進入主表：

INSERT INTO [WHAnalysis].[dbo].[Control_cReport] 
SELECT 
    [ProcessKey] = 12, 
    [ReportTechKey] = 1 
FROM WHAnalysis.dbo.Controltb_ReportingScheduler_jq

我得到這個錯誤：

Msg 547, Level 16, State 0, Line 1 The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Control_cReport_cReportTech". The conflict occurred in database "WHAnalysis", table "dbo.Control_cReportTech", column 'ReportTechKey'. The statement has been terminated.

來源

2012-10-08 whytheq

的問題是，因爲你正試圖INSERT在ProcessKey字段中的值，這並不在Control_cReportTech表中存在。

我會改變INSERT語句來指定要嘗試INSERT到田間地頭：

INSERT INTO [Control_cReport] (ProcessKey, ReportTechKey) 
SELECT 12 as ProcessKey, 1 as ReportTechKey; 
FROM WHAnalysis.dbo.Controltb_ReportingScheduler_jq;

見SQL Fiddle With Demo

使用上面的查詢，而不是當前的查詢，因爲當列不指定時，它會嘗試按照表結構的順序插入值。所以它試圖在ReportTechKey列中插入一個值12，這個列違反了外鍵。

指定要插入數據的列的順序總是好得多。

來源

2012-10-08 11:10:32 Taryn

...我認爲'[ProcessKey] = 12'等於'12作爲ProcessKey'？！ – whytheq

@whytheq不同之處在於我指定了'INSERT'中的列'INSERT INTO [Control_cReport]（ProcessKey，ReportTechKey）'，你不是那麼不知道該把值放在哪裏 – Taryn

ahhh -nice一;只是在'SELECT'子句中按正確的順序放置這些列是可行的，但如果將來使用你的方法，那麼代碼將更具防禦性，因爲它避免了模式更改的問題 – whytheq

爲什麼有外鍵衝突

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