You should NEVER store a computed value within a (static) row.
Every computed value should be selected, computed & displayed as needed.

True. But if it is really needed, then for 11g and up, virtual columns could be used. Although, they are some restrictions.

You should NEVER store a computed value within a (static) row.

I was wondering about using dense_rank but I don't have that experience besides Java & Dot.Net.

Pablolee,
Please don't take it that way.

The replies from all above are appreciated and all agreed that the requirement is not correct.

Again, I am not Oracle expert to that level

and what I got is very tricky problem.

No fruits to enjoy but again appreciate the replies.

When Editing the row, user is only allowed to change the date in the row. When date is changed then 2 things I need to do: 1) Compare the date of the row changed with the dates of the rest of the rows (up & down). 2) If the date that is updated is less than the above row (for example) then the "project display nbr" is also updated.

create or replace view your_datagrid_v as
select start_date,
       row_number() over (order by start_date asc) project_display_nbr,
       name
from   yourTable;

select start_date          ,
       project_display_nbr ,
       name
from   your_datagrid_v
order by project_display_nbr asc;

Should I drop table view after the process is completed? I mean create a View each time a new process start.

My question: Should I drop table view after the process is completed? I mean create a View each time a new process start.

G A view contains no data itself. Can only be used on functions, procedures, types, views, or packages - it will not work on tables.