Trouble with Columns

I've got a big dataset with lots of stuff in it.

I need to make another dataset containing some of the columns in the original dataset.

 DataColumn dcJobCode = dsOriginal.Tables[0].Columns["JobCode"];
DataSet dsSmaller = new DataSet();
dsSmaller.Tables.Add();
dsSmaller.Tables[0].Columns.Add(dcJobCode); //this is the line that bombs

each time I do this though, using other methods as well as the one above, I'm told that
"Column 'JobCode' already belongs to another DataTable.".

I've even tried clearing and nulling the original dataset, but I still get the same message.
Help!You need to create a new instance of a DataColumn and copy the contents from the original. At the moment your simply copying the address [in memory] of the original DataColumn.
Thanks for your help, but I can't work out how to copy the data.

Do I have to set up a loop and copy each row of the column across manually? I can't see any methods of the DataColumn object that do this?

Thanks again.

Troubles with INSERT command

Hi, I am currently trying to INSERT selected rows from table Cart intotable Orders. Table Cart has columns Id_record(autonumber),Id_title(LongInt), Customer(text), Table Orders has the same columnsand also column Order_ID. When I delete this colums Order_ID and insertonly values from table cart like this, it works.
queryString = "INSERT INTO [Orders] SELECT * FROM [Cart] WHERE Cart.Customer = @dotnet.itags.org.user"
Dim dbCommand as OleDbCommand = new OleDbCommand(queryString, myConnection)
dbCommand.Parameters.Add(New OleDbParameter("@dotnet.itags.org.user", OleDbType.Char, 20))
dbCommand.Parameters("@dotnet.itags.org.user").Value = user.Identity.Name

Troubles begin, when I try to insert also that randomly generated number into my table Orders. I use this code...
Dim myConnection as OleDbConnection = new OleDbConnection(connectionString)
queryString = "INSERT INTO [Orders] SELECT *, @dotnet.itags.org.random as Order_ID FROM [Cart] WHERE Cart.Customer = @dotnet.itags.org.user"
Dim dbCommand as OleDbCommand = new OleDbCommand(queryString, myConnection)
dbCommand.Parameters.Add(New OleDbParameter("@dotnet.itags.org.user", OleDbType.Char, 20))
dbCommand.Parameters("@dotnet.itags.org.user").Value = user.Identity.Name
Randomize()
dbCommand.Parameters.Add(New OleDbParameter("@dotnet.itags.org.random", OleDbType.Integer, 20))
dbCommand.Parameters("@dotnet.itags.org.random").Value = ((Int32.MaxValue) * Rnd)
I always ger error "Duplicate output destination in Id_record" andhave no idea, how to fix it. Could pls somebody help me? Or could ugive me some link on some good INSERT tutorial?

If both the tables are not EXCTLY similar in columns you would get errors. So list out the column names xplicitly.
INSERT INTO col1, col2, col3 SELECT cart.col1, cart,col2, cart.col3 FROM cart WHERE Cart.Customer = @.user"

Exclude the identity column since you cannot manually insert into it.

Hm, so I changed my query into something like this, but now im gettingOverflow error. Does someone know what Overflow error means? Could bethis error caused bz the fact, that Id_record is autonumber in Carttable but I am trying to isnert it as integer in Orders table?

Dim myConnection as OleDbConnection = new OleDbConnection(connectionString)
queryString = "INSERT INTO [Orders] (Id_record,Id_title, Customer, Id_order) SELECT Id_record, Id_title, Customer,@.user FROM [Cart] WHERE Cart.Customer = @.user"
Dim dbCommand as OleDbCommand = new OleDbCommand(queryString, myConnection)
Randomize()
Dim Rand As Int32 = ((Int32.MaxValue) * Rnd)
dbCommand.Parameters.Add(New OleDbParameter("@.random", OleDbType.Integer, 20))
dbCommand.Parameters("@.random").Value = Rand
dbCommand.Parameters.Add(New OleDbParameter("@.user", OleDbType.Char, 20))
dbCommand.Parameters("@.user").Value = user.Identity.Name


queryString = "INSERT INTO [Orders] (Id_record, Id_title, Customer, Id_order) SELECT Id_record, Id_title, Customer, @.user FROM [Cart] WHERE Cart.Customer = @.user"

is Orders.Id_order column a autonumber column? if so you cant explicity insert into this column.
providing the sqldatatype(integer?) of Cart.Id_record is the same type as Orders.ID_record it shouldnt be a problem.
Well, Cart.ID_Record is the autonumber and Orders.ID_record is theinteger. I need to insert this autonumber into Orders.Id_record asinteger.
Orders.Id_order is normal Integer.
Edit: Hm, when i remove the last column from orders and try to insertjust first 3 columns, everything works fine. So the problem is either in the declaration of random variable or in the was it is placed in SQO query.

queryString = "INSERT INTO [Orders] (Id_record, Id_title, Customer, Id_order) SELECT Id_record, Id_title, Customer,@.user FROM [Cart] WHERE Cart.Customer = @.user"

whats with the @.user in the select list?
waht are you trying to do there with it?