将数据插入到3个表中的存储过程。不工作。

Question

我有3个表 -

1. Country (CountryName, CID (PK- AutoIncrement)) 
2. State (SID(PK- AutoIncrement), StateName, CID (FK to Country) 
3. City (CityName, CID, SID (FK to State) 

现在我只需要姓名插入到与国家或地区名称，Statename的和CITYNAME三个表。该标识需要得到更新。

Create PROCEDURE sp_place(
    @CountryName char(50), 
    @StateName varchar(50), 
    @CityName nchar(20) 
    ) 
AS 
DECLARE @CountryID int, @StateID int, @CityID int; 

Set NOCOUNT OFF 

BEGIN TRANSACTION 

INSERT INTO dbo.Country VALUES (@CountryName); 
SET @CountryID = SCOPE_IDENTITY(); 

IF @@ERROR <> 0 
BEGIN  
ROLLBACK  
RETURN 
END 

Insert into dbo.State VALUES (@StateName, @CountryID); 
SET @StateID = SCOPE_IDENTITY(); 
IF @@ERROR <> 0 
BEGIN  
ROLLBACK  
RETURN 
END 

Insert into dbo.City VALUES (@CityName, @StateID); 
SET @CityID= SCOPE_IDENTITY(); 

Commit 

当我输入国家两次时，值不应该改变。 例如：如果我输入印度的国家ID = 1的值，那么当我再次进入印度时，CountryID的值不应增加。

我该怎么做？每个插入我的SP都会改变。

Answer 1

插入重复的国家可以检查该国已经存在并检索countryID

IF NOT EXISTS(Select 1 FROM Country Where CountryName=@Country) 
BEGIN 
    INSERT INTO dbo.Country VALUES (@CountryName); 
    SET @CountryID = SCOPE_IDENTITY(); 
END 
ELSE 
    Select @CountryID = CountryID From Country Where CountryName=@Country 

设置Unique Constraint如果需要，您可以对State和City执行相同的操作。

Answer 2

您需要MERGE语法

http://technet.microsoft.com/en-us/library/bb510625.aspx

或手动检查（即：与IF EXISTS (...)），为国家的插入之前存在。

Answer 3

你为什么不上国家或地区名称列不会让你在所有

Answer 4

Hello try with this syntax 

IF EXISTS (SELECT * FROM Country WHERE CountryName= @CountryName) 
BEGIN 
    UPDATE dbo.Country 
    SET CountryName = @CountryName 
    WHERE CountryId = (SELECT CountryId FROM dbo.Country WHERE CountryName= @CountryName); 
END 
ELSE 
BEGIN 
    INSERT INTO dbo.Country(CountryName) VALUES (@CountryName); 

END 

-- For the identity you must just add identity to your column in your creation script