Default values on new row

7 Dec 2006 7:44 AM

Gudni G. Sigurdsson

Hi.
I have a WinForms app and a SQL Server database. When the user adds a new
row to a table (say table Orders with columns OrderNo and CustNo ), I want to
programmatically supply values for CustNo (current user) and OrderNo (number
of orders by customer CustNo incremented by one). What is the standard way
to do this? Should I subscribe to some event, like TableNewRow or, should I
perhaps do it on the database level (triggers)? Any advice would be
appreciated.
Gudni

7 Dec 2006 9:26 PM

Marina Levit [MVP]

How is the user adding the new row? Are you providing them a way to do it?
In which case, you should do it in the same place.

Additionally, look into the DefaultValue property of columns in a DataTable
(I am assuming you are using one, you didn't provide a lot of detail), you
can set some defaults up that way.

Or are you trying to do it right as the insert as being done in the
database? I don't see how triggers would do it - your trigger wouldn't have
the username of the user in your application.

It's very hard to answer without getting more specific details.

Show quote

"Gudni G. Sigurdsson" <GudniGSigurds***@discussions.microsoft.com> wrote in
message news:3D802F63-65D9-4736-A0AF-77FD833745DB@microsoft.com...
> Hi.
> I have a WinForms app and a SQL Server database. When the user adds a new
> row to a table (say table Orders with columns OrderNo and CustNo ), I want
> to
> programmatically supply values for CustNo (current user) and OrderNo
> (number
> of orders by customer CustNo incremented by one). What is the standard
> way
> to do this? Should I subscribe to some event, like TableNewRow or, should
> I
> perhaps do it on the database level (triggers)? Any advice would be
> appreciated.
> Gudni

8 Dec 2006 8:00 AM

Gudni G. Sigurdsson

Hi Marina and thank you for your response.

I have a dataGridView, a bindingSource and a bindingNavigtor wired up. The
data source of the binding source is a table in a dataSet contained in a DAL
module separate from my UI module. When the user clicks on the addNewItem
button in the binding navigator, I want to generate my default values.

I have come up with a way to do this. In the
bindingNavigatorAddNewItem_Click event handler, I check the last row in the
grid, take the value of OrderNo and increment it by one. The value for
CustNo is known from elsewhere. This works, but I suspect that it should
preferably be done in the DAL module at the database level?

Also, I might have instead of a dataGridView a detail view of a single
record in my (Orders)table. I could probably do something similar, but when
I started to think about this problem, I imagined that I would run a query
against my database down in the DAL module to find out the last OrderNo for
the current CustNo. This is perhaps unnecessary complicated. I would
appreciate any suggestions.

Sincerely,
Gudni

Show quote

"Marina Levit [MVP]" wrote:

> How is the user adding the new row? Are you providing them a way to do it?
> In which case, you should do it in the same place.
>
> Additionally, look into the DefaultValue property of columns in a DataTable
> (I am assuming you are using one, you didn't provide a lot of detail), you
> can set some defaults up that way.
>
> Or are you trying to do it right as the insert as being done in the
> database? I don't see how triggers would do it - your trigger wouldn't have
> the username of the user in your application.
>
> It's very hard to answer without getting more specific details.
>
> "Gudni G. Sigurdsson" <GudniGSigurds***@discussions.microsoft.com> wrote in
> message news:3D802F63-65D9-4736-A0AF-77FD833745DB@microsoft.com...
> > Hi.
> > I have a WinForms app and a SQL Server database. When the user adds a new
> > row to a table (say table Orders with columns OrderNo and CustNo ), I want
> > to
> > programmatically supply values for CustNo (current user) and OrderNo
> > (number
> > of orders by customer CustNo incremented by one). What is the standard
> > way
> > to do this? Should I subscribe to some event, like TableNewRow or, should
> > I
> > perhaps do it on the database level (triggers)? Any advice would be
> > appreciated.
> > Gudni
>
>
>