高级问题

oracle里有张表persontable(ID,R1,R2)
其中r1 (varchar2)4000,r2 (varchar2)3800; OracleConnection connect = new OracleConnection();
            connect.ConnectionString = ";";
            connect.Open();
            OracleCommand cmd = connect.CreateCommand();
            cmd.Connection = connect;
            cmd.CommandText = "";
            
            Random rnd = new Random();
            OracleParameter[] p = new OracleParameter[2];
            for (int i = 1; i <= 10; i++)
            {
                
                    p[0] = cmd.CreateParameter();
                    p[0].ParameterName = ":R1";                    
                    p[0].DbType = DbType.Binary;
                    p[0].Size = 4000;
                    p[0].Value = new Byte[4000] ;
                    p[0].Direction = ParameterDirection.Input;
                    cmd.Parameters.Add(p[0]);
                                       p[1] = new OracleParameter();
                    p[1].ParameterName = ":R2";                   
                    p[1].DbType = DbType.Binary;
                    p[1].Size = 3800;  
                    p[1].Value = new Byte[3800] ;
                    p[1].Direction = ParameterDirection.Input;
                    cmd.Parameters.Add(p[1]);
                    cmd.CommandText = "insert into persontable(ID,R1,R2) values(" + i.ToString() + ",R1,:R2)";
                    cmd.ExecuteNonQuery();
               
            }
            cmd.Dispose();
            connect.Dispose();
            Console.Read();
可是经常在cmd.ExecuteNonQuery();
出问题。
ORA-12899: value too large for column "SPM_TST_OWNER"."PERSONTABLE"."R2" (actual: 4000, maximum: 3800)我能想到的问题就是.net command最大执行的sql语句长度是2000.可是要插入大于2000的就要用这种方式。可是要怎么写就是忘了，大家帮忙看看啊