Update issue with stored procedure - sql-server

Question

I am working with a Old tool and the database that was connected to this tool in long gone. I am new at this and need some help understanding this. I need help with writing the code i tried and error-ed out every time.
public void UpdateUser(string NewUser, string OldUser)
{
using (SqlConnection con = HSDatabaseConnection())
{
using (SqlCommand cmd = new SqlCommand("UpdateNames", con))
{
cmd.CommandType = System.Data.CommandType.StoredProcedure;
cmd.Parameters.Add("#LogonName", System.Data.SqlDbType.VarChar).Value = NewUser;
cmd.Parameters.Add("#OldLogonName", System.Data.SqlDbType.VarChar).Value = OldUser;
cmd.ExecuteNonQuery();
}
con.Close();
}
}
I have 4 tables the only thing each table has in common is the column name "AN". I need to update "AN" if a agent changes there name legally
so far I have come up with this procedure
USE [HSDB]
GO
/****** Object: StoredProcedure [dbo].[UpdateNames] Script Date: 9/16/2016 12:32:33 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[UpdateNames]
--Add the parameters for the stored procedure here
#AN varchar(MAX)
AS
BEGIN
--SET NOCOUNT ON added to prevent extra result sets from
--interfering with SELECT statements.
SET NOCOUNT ON;
--Insert statements for procedure here
UPDATE Att
SET AN = #AN
WHERE (AN = #AN)
UPDATE MS
SET AN = #AN
WHERE (AN = #AN)
UPDATE Lost
SET AN = #AN
WHERE (AN = #AN)
UPDATE WeeklyCharges
SET AN = #AN
WHERE (AN = #AN)
END
Can some one please tell me what i am doing wrong. Thank you

Answer 1

Issue 1:
your c# code is passing 2 paramaters #LogonName and #OldLogonName but your stored procedure is only accepting 1 parameter #AN. So that should error out.
Issue 2:
all of your update statements are setting AN = to itself because you are saying when AN = #AN then set AN = #AN....
Without having more detail about the error and your data structures, which you should include in the future, it is a little difficult to say. However, you probably could do something like this in SQL-Server 2012 +:
USE [HSDB]
GO
/****** Object: StoredProcedure [dbo].[UpdateNames] Script Date: 9/16/2016 12:32:33 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[UpdateNames]
--Add the parameters for the stored procedure here
#LogonName varchar(100)
,#OldLogonName varchar(100)
AS
BEGIN
--SET NOCOUNT ON added to prevent extra result sets from
--interfering with SELECT statements.
SET NOCOUNT ON;
--Insert statements for procedure here
BEGIN TRY
IF NOT EXISTS (SELECT * FROM LogOnOrUserTable WHERE LogonName = #OldLogonName)
BEGIN
;THROW 51000, 'Old Logon Name Does Not Exists', 1
END
BEGIN TRANSACTION
UPDATE Att
SET AN = #LogonName
WHERE (AN = #OldLogonName)
UPDATE MS
SET AN = #LogonName
WHERE (AN = #OldLogonName)
UPDATE Lost
SET AN = #LogonName
WHERE (AN = #OldLogonName)
UPDATE WeeklyCharges
SET AN = #LogonName
WHERE (AN = #OldLogonName)
COMMIT TRANSACTION
END TRY
BEGIN CATCH
IF ##TRANCOUNT > 0 ROLLBACK TRANSACTION
;THROW
END CATCH
END
What it does:
first tests to see if the old user name exists and if it doesn't throws an error.
then updates all of the tables where AN = old logon name and sets it to the new logon name
if any one of those fails it rolls back the transaction and throws an error so that you don't have a change half made