DataTable的UPdata操作Oracle遇到的问题

Question

string connstr = "Data Source=TEST;User ID=eprowb2b;Password=eprowb2b";
            OracleConnection conn = new OracleConnection(connstr);
            OracleCommand cmd = new OracleCommand();
            cmd.Connection = conn;
            int rValue = 0;
            try
            {
                conn.Open();
                cmd.CommandText = "select " + cloumnName + " from " + tableName;
                OracleDataAdapter da = new OracleDataAdapter(cmd);
                OracleCommandBuilder cmdBuilder = new OracleCommandBuilder(da);
                da.InsertCommand = cmdBuilder.GetInsertCommand();
                rValue = da.Update(table);
                da.Dispose();
            }
            catch (OracleException ex)
            {
                throw ex;
            }
            finally
            {
                conn.Close();
            }问题是我的表里面有个主键ID（通过COMPANY_SEQ.NEXTVAL可以得到），现在我要怎么在C#代码中直接提交COMPANY_SEQ.NEXTVAL得到的值。