Question

I have stored procedure which update Customers and a datagridview to work with the data.
Editing not primary filed values works well, but if I try to update primary key filed value I get an exception “Concurrency violation: the UpdateCommand affected 0 of the expected 1 records.”

This is my sp:

create procedure dbo.UpdateCustomers
@CustomerID nchar(5),
@CompanyName nvarchar(40),
@ContactName nvarchar(30),
@ContactTitle nvarchar(30),
@Address nvarchar(60),
@City nvarchar(15),
@Region nvarchar(15),
@PostalCode nvarchar(10),
@Country nvarchar(15),
@Phone nvarchar(24),
@Fax nvarchar(24)
as
update Customers
set CustomerID = @CustomerID, CompanyName = @CompanyName, ContactName = @ContactName, ContactTitle = @ContactTitle, Address = @Address,
    City = @City, Region = @Region, PostalCode = @PostalCode, Country = @Country, Phone = @Phone, Fax = @Fax
where CustomerID = @CustomerID
go

And in code:

public void UpdateData()
            {
                using (var cn = new SqlConnection(_cs))
                {

                    ....

                    var updateCmd = new SqlCommand("UpdateCustomers", cn);
                    updateCmd.CommandType = CommandType.StoredProcedure;

                    updateCmd.Parameters.Add(
                        new SqlParameter("@CustomerID", SqlDbType.NVarChar, 5, "CustomerID"));
                    updateCmd.Parameters.Add(
                        new SqlParameter("@CompanyName", SqlDbType.NVarChar, 40, "CompanyName"));
                    updateCmd.Parameters.Add(
                        new SqlParameter("@ContactName", SqlDbType.NVarChar, 30, "ContactName"));
                    updateCmd.Parameters.Add(
                        new SqlParameter("@ContactTitle", SqlDbType.NVarChar, 30, "ContactTitle"));
                    updateCmd.Parameters.Add(
                        new SqlParameter("@Address", SqlDbType.NVarChar, 60, "Address"));
                    updateCmd.Parameters.Add(
                        new SqlParameter("@City", SqlDbType.NVarChar, 15, "City"));
                    updateCmd.Parameters.Add(
                        new SqlParameter("@Region", SqlDbType.NVarChar, 15, "Region"));

                    ...

                    _da.UpdateCommand = updateCmd;
                    var count = _da.Update(_ds, "Customers"); //exception
                    GetData();
                }
            }

I understand that when this procedure executed with new CustomerID there is no rows affected to update. But, how can I pass from application new and old CustomerID?

Something like this in SQL:

update Customers set CustomerID = 'NEWVALUE' where CustomerID = 'BSBEV'
....

etc.

Answer 1

You should never update the primary key.

I suspect that you are getting this error because you are trying to update a row that does not exist.

You may want to read up on Optimisitc Concurrency.

If you want to change the Primary key, you should probably just insert a new record. What is your reason for doing this?