SQL : can't get IDENTITY value in Trigger

I am newbie in SQL.I am creating a dummy project.In my project, I have one register page and I want to create a UserName(FirstName + LastName + UserID).But the problem is, I cant catch the UserID value.I have used both After Trigger and Instead Of Trigeer. Below is my script -

Table -

CREATE TABLE UserInfo
(
    UserID INT IDENTITY(1,1),
    FirstName NVARCHAR(500),
    LastName NVARCHAR(500),
    [Password] NVARCHAR(200),
    EmailID NVARCHAR(200),
    [Address] NVARCHAR(500),
    CountryID INT,
    StateID INT,
    UserName NVARCHAR(500)
)

Proc of Insert Data -

CREATE PROC Create_User    
 @FirstName NVARCHAR(500),    
 @LastName NVARCHAR(500),    
 @Password NVARCHAR(200),    
 @EmailID NVARCHAR(200),    
 @Address NVARCHAR(500),    
 @CountryID INT,    
 @StateID INT,    
 @UserID INT OUTPUT    
AS    
 BEGIN    
 INSERT INTO UserInfo (FirstName,LastName,[Password],EmailID,[Address],CountryID,StateID)    
 VALUES    
 (@FirstName,@LastName,@Password,@EmailID,@Address,@CountryID,@StateID)    

 SET @UserID = SCOPE_IDENTITY();    

 END 

After Trigger -

CREATE TRIGGER Create_UserName
ON UserInfo
AFTER INSERT
AS
BEGIN
DECLARE @_UName VARCHAR(200);
SET @_UName = (SELECT FirstName+LastName+Cast(UserID AS NVARCHAR(100)) from INSERTED )

INSERT INTO UserInfo (UserName) VALUES (@_UName)
END
    GO

Output - Inserted two rows

Instead Of Trigger -

CREATE TRIGGER Create_UserName
ON UserInfo
INSTEAD OF INSERT
AS
BEGIN
DECLARE @UName NVARCHAR(200);
DECLARE @FName NVARCHAR(200);
DECLARE @LName NVARCHAR(200);
DECLARE @UPassword NVARCHAR(200);
DECLARE @UEmailID NVARCHAR(200);
DECLARE @UAddress NVARCHAR(200);
DECLARE @UCountryID INT;
DECLARE @UStateID INT;
SET @UName = (SELECT FirstName+LastName+Cast(UserID AS NVARCHAR(100)) from开发者_开发问答 INSERTED )
SET @FName = (SELECT FirstName from INSERTED )
SET @LName = (SELECT LastName from INSERTED )
SET @UPassword = (SELECT [Password] from INSERTED )
SET @UEmailID = (SELECT EmailID from INSERTED )
SET @UAddress = (SELECT [Address] from INSERTED )
SET @UCountryID = (SELECT CountryID from INSERTED )
SET @UStateID = (SELECT StateID from INSERTED )




INSERT INTO UserInfo (FirstName,LastName,[Password],EmailID,[Address],CountryID,StateID,UserName)  
VALUES (@FName,@LName,@UPassword,@UEmailID,@UAddress,@UCountryID,@UStateID,@UName)
END
    GO

Output - this works fine but Identity is 0.

Please tell me how I can do this?

Thanks in advance.

You have problems

• Why do you have a stored proc and INSTEAD OF? Use either a stored proc OR an instead of trigger: not both
• Second, the triggers are coded for one row only
• The after trigger is inserting a new row, should be an update

As to why:

The stored proc has no INSERT to trap the IDENTITY value: the scope for the INSERT is actually the instead of trigger. If you switch to @@IDENTITY (bad practice) you'd get the IDENTITY value from the AFTER trigger.

What to do:

• Drop both of the triggers: they add no value

• Either add a computed column to the table if UserName cannot be changed

eg

ALTER TABLE UserInfo ADD UserName AS FirstName+LastName+Cast(UserID AS NVARCHAR(100)

• ...or add an UPDATE to the stored proc UserName could be changed later

eg

CREATE PROC Create_User    
...
AS    

SET NOCOUNT, XACT_ABORT ON

BEGIN TRY
 BEGIN TRAN

 INSERT INTO UserInfo
   (FirstName,LastName,[Password],EmailID,[Address],CountryID,StateID)    
 VALUES    
   (@FirstName,@LastName,@Password,@EmailID,@Address,@CountryID,@StateID)

 SET @UserID = SCOPE_IDENTITY();    

 UPDATE UserInfo
 SET UserName = @FirstName+@LastName+Cast@UserID AS NVARCHAR(100)
 WHERE UserID = @UserID

   COMMIT TRAN
END TRY
BEGIN CATCH
   IF XACT_STATE() <> 0 ROLLBACK TRAN
END CATCH
GO

Try this trigger:

CREATE TRIGGER Create_UserName
ON UserInfo
AFTER INSERT
AS
BEGIN
    --DECLARE @_UName VARCHAR(500), @user_id INT
    --SELECT @_UName = FirstName + LastName + Cast(UserID AS NVARCHAR(100)), @user_id = UserId FROM INSERTED

    UPDATE UserInfo 
    SET UserName = i.FirstName + i.LastName + Cast(i.UserID AS NVARCHAR(100))
    FROM UserInfo u
    INNER JOIN Inserted I ON (i.UserId = u.UserId)
    --WHERE   UserId = @user_id
END

If you have SQL-Server 2005+ you can use the output clause of the insertstatement.

CREATE PROC Create_User    
 @FirstName NVARCHAR(500),    
 @LastName NVARCHAR(500),    
 @Password NVARCHAR(200),    
 @EmailID NVARCHAR(200),    
 @Address NVARCHAR(500),    
 @CountryID INT,    
 @StateID INT,    
 @UserID INT OUTPUT    
AS    
 BEGIN
    DECLARE @OV Table (id int);

    INSERT INTO UserInfo (FirstName,LastName,[Password],EmailID,[Address],CountryID,StateID)
    inserted.id into @OV  
    VALUES (@FirstName,@LastName,@Password,@EmailID,@Address,@CountryID,@StateID)    

    SELECT @UserID = id FROM @OV;    
    update UserInfo set UserName = FirstName + LastName + Cast(UserID AS NVARCHAR) where UserID  = @userid
END 

EDIT: Missing keyword added, update of UserName column