Important drawback in .NET DataSet.

[Lester Moreno]

Hello all,
Up to now C# have been an great experience but I found myself in a end of
the road problem.

Let say that you have two windows program running on a local network area.

User1 and user2 have the same information in the dataset and user1 makes a
change, unless user2 refill all his tables in his dataset he can't see the
new changes made by User1 and it can easily overwrite them.

Please, if you have some ideas how to make a Sync process please let me
know.
Thanks!

[Lester Moreno]

I think that ADO.NET was design as a web server engine, I have look all
over of a way to Syncronise two users loaded dataset and all I can thing is
do a fill each time the user try to make a search!

How would you do it?

Thanks!!

"codewriter" <co**************@yahoo.com> wrote in message
news:Vt*******************@news20.bellglobal.com.. .

Hi Lester,

ADO.NET uses optimistic locking. DataSet is the same as disconnected
recodset. And I think it is properly designed this way. You do not really
want your database being locked when a user opens a dataset. So, I do not
think it is a drawback at all, it's by design.
If you want to implement locking you should use different approach.

"Lester Moreno" <le**********@covad.com> wrote in message
news:bg**********@sun-news.laserlink.net...

Hello all,
Up to now C# have been an great experience but I found myself in a end of the road problem.

Let say that you have two windows program running on a local network area.
User1 and user2 have the same information in the dataset and user1 makes a change, unless user2 refill all his tables in his dataset he can't see the new changes made by User1 and it can easily overwrite them.

Please, if you have some ideas how to make a Sync process please let me
know.
Thanks!

[Lester Moreno]

Yes,

I think that what I need to do, but I can't find any docs about how to store
the state in the database!
Do you have some link's that I can read about this,

Thank you a lot!

"codewriter" <co**************@yahoo.com> wrote in message
news:W5*******************@news20.bellglobal.com.. .

You are thinking in the Client-Server mode. This means that you are caching information on the client, i.e. storing the state on the client instead of
server. Better way would be to think in a N-tiered application way. In the
latter case, it is required to store the state in the database, at least
this is what MS recommends. In this case, you have only one source of
information, and you do not need to synchronize anything. And you are right, every time user makes a search you should go to the database and get the
data.
On top of that, if you want to prevent other users from overwriting, you
should implement locking in the database. One way of doing it would be to
use a flag field that would indicate that this particular record is being
edited by somebody, and whoever tries to overwtite it should get a message
that the record is locked. This poses some drawbacks, of course. But it will work.

"Lester Moreno" <le**********@covad.com> wrote in message
news:bg**********@sun-news.laserlink.net...

I think that ADO.NET was design as a web server engine, I have look all
over of a way to Syncronise two users loaded dataset and all I can thing

is

do a fill each time the user try to make a search!

How would you do it?

Thanks!!

"codewriter" <co**************@yahoo.com> wrote in message
news:Vt*******************@news20.bellglobal.com.. .

Hi Lester,

ADO.NET uses optimistic locking. DataSet is the same as disconnected
recodset. And I think it is properly designed this way. You do not really want your database being locked when a user opens a dataset. So, I do not think it is a drawback at all, it's by design.
If you want to implement locking you should use different approach.

"Lester Moreno" <le**********@covad.com> wrote in message
news:bg**********@sun-news.laserlink.net...
> Hello all,
>
>
> Up to now C# have been an great experience but I found myself in a

end

of

> the road problem.
>
> Let say that you have two windows program running on a local network

area.

>
> User1 and user2 have the same information in the dataset and user1 makes

a

> change, unless user2 refill all his tables in his dataset he can't

see the

> new changes made by User1 and it can easily overwrite them.
>
> Please, if you have some ideas how to make a Sync process please let

me > know.
>
>
> Thanks!
>
>

[sandman]

One way to lock records is to create a column in your
table (call it Status or something). When the user
accesses a record, you set the Status to "in use" (you
define the value) and commit the record back to the
database. When the user is either done or cancels
editing, then the Status is set back to an "available"
status. Timing needs to be managed carefully because
commits (or Update) to the database make all changes
permenent. And the only way another user is going to see
this is to refresh the dataset.

----Original Message-----

Yes,

I think that what I need to do, but I can't find any docs about how to storethe state in the database!
Do you have some link's that I can read about this,

Thank you a lot!

"codewriter" <co**************@yahoo.com> wrote in message
news:W5*******************@news20.bellglobal.com. ..

You are thinking in the Client-Server mode. This means that you are

caching

information on the client, i.e. storing the state on the client instead of server. Better way would be to think in a N-tiered application way. In the latter case, it is required to store the state in the database, at least this is what MS recommends. In this case, you have only one source of information, and you do not need to synchronize anything. And you are

right,

every time user makes a search you should go to the

database and get the data.
On top of that, if you want to prevent other users from overwriting, you should implement locking in the database. One way of doing it would be to use a flag field that would indicate that this particular record is being edited by somebody, and whoever tries to overwtite it should get a message that the record is locked. This poses some drawbacks, of course. But itwill

work.

"Lester Moreno" <le**********@covad.com> wrote in

message news:bg**********@sun-news.laserlink.net...

> I think that ADO.NET was design as a web server engine, I have look all > over of a way to Syncronise two users loaded dataset and all I can thing

is

> do a fill each time the user try to make a search!
>
> How would you do it?
>
> Thanks!!
>
> "codewriter" <co**************@yahoo.com> wrote in

message > news:Vt*******************@news20.bellglobal.com.. .
> > Hi Lester,
> >
> > ADO.NET uses optimistic locking. DataSet is the same as disconnected > > recodset. And I think it is properly designed this way. You do not really

> > want your database being locked when a user opens a

dataset. So, I do not

> > think it is a drawback at all, it's by design.
> > If you want to implement locking you should use

different approach. > >
> > "Lester Moreno" <le**********@covad.com> wrote in message > > news:bg**********@sun-news.laserlink.net...
> > > Hello all,
> > >
> > >
> > > Up to now C# have been an great experience but I found myself in aend > of
> > > the road problem.
> > >
> > > Let say that you have two windows program running

on a local network > area.
> > >
> > > User1 and user2 have the same information in the dataset and user1 makes

> a
> > > change, unless user2 refill all his tables in his

dataset he can't

see > the
> > > new changes made by User1 and it can easily

overwrite them. > > >
> > > Please, if you have some ideas how to make a Sync

process please let me

> > > know.
> > >
> > >
> > > Thanks!
> > >
> > >
> >
> >
>
>

.

[Jay B. Harlow [MVP - Outlook]]

Lester,
I believe you can use SQL Server 2000 Notification Services to achieve what
you want.

http://msdn.microsoft.com/library/de...arted_4mn9.asp

Hope this helps
Jay

"Lester Moreno" <le**********@covad.com> wrote in message
news:bg**********@sun-news.laserlink.net...

Hello all,
Up to now C# have been an great experience but I found myself in a end of
the road problem.

Let say that you have two windows program running on a local network area.

User1 and user2 have the same information in the dataset and user1 makes a
change, unless user2 refill all his tables in his dataset he can't see the
new changes made by User1 and it can easily overwrite them.

Please, if you have some ideas how to make a Sync process please let me
know.
Thanks!

[Lester Moreno]

Hello,
So what you are saying is not to use Dataset and star using DataReader to
access the data directly?

Thanks,
Lester
"codewriter" <co**************@yahoo.com> wrote in message
news:ZO*******************@news20.bellglobal.com.. .

Well, I don't know about the links, but in order to save the state in the
database you will have to create tables and store your data in them. If you give me a bit more info about your particular project, I will be able to
write some code for you if you like.

Actually, this article deals with general design recommendations for .NET:
http://msdn.microsoft.com/vstudio/us...apparchch2.asp
Regards

"Lester Moreno" <le**********@covad.com> wrote in message
news:bg**********@sun-news.laserlink.net...

Yes,

I think that what I need to do, but I can't find any docs about how to store

the state in the database!
Do you have some link's that I can read about this,

Thank you a lot!

"codewriter" <co**************@yahoo.com> wrote in message
news:W5*******************@news20.bellglobal.com.. .

You are thinking in the Client-Server mode. This means that you are

caching

information on the client, i.e. storing the state on the client instead of

server. Better way would be to think in a N-tiered application way. In the latter case, it is required to store the state in the database, at

least this is what MS recommends. In this case, you have only one source of
information, and you do not need to synchronize anything. And you are

right,

every time user makes a search you should go to the database and get the data.
On top of that, if you want to prevent other users from overwriting, you should implement locking in the database. One way of doing it would be to use a flag field that would indicate that this particular record is being edited by somebody, and whoever tries to overwtite it should get a message that the record is locked. This poses some drawbacks, of course. But it will

work.

"Lester Moreno" <le**********@covad.com> wrote in message
news:bg**********@sun-news.laserlink.net...
> I think that ADO.NET was design as a web server engine, I have look all > over of a way to Syncronise two users loaded dataset and all I can thing is
> do a fill each time the user try to make a search!
>
> How would you do it?
>
> Thanks!!
>
> "codewriter" <co**************@yahoo.com> wrote in message
> news:Vt*******************@news20.bellglobal.com.. .
> > Hi Lester,
> >
> > ADO.NET uses optimistic locking. DataSet is the same as

disconnected > > recodset. And I think it is properly designed this way. You do not
really
> > want your database being locked when a user opens a dataset. So, I do not
> > think it is a drawback at all, it's by design.
> > If you want to implement locking you should use different approach. > >
> > "Lester Moreno" <le**********@covad.com> wrote in message
> > news:bg**********@sun-news.laserlink.net...
> > > Hello all,
> > >
> > >
> > > Up to now C# have been an great experience but I found myself in a end

> of
> > > the road problem.
> > >
> > > Let say that you have two windows program running on a local network > area.
> > >
> > > User1 and user2 have the same information in the dataset and

user1 makes
> a
> > > change, unless user2 refill all his tables in his dataset he

can't see

> the
> > > new changes made by User1 and it can easily overwrite them.
> > >
> > > Please, if you have some ideas how to make a Sync process please

let me
> > > know.
> > >
> > >
> > > Thanks!
> > >
> > >
> >
> >
>
>

[Lester Moreno]

Thank you sandman,

It looks like that ADO.NET is not design to do small application using
record looking and accessing the data without having to cash them. For
example VFoxpro use dataviews that are retrieved from SQL each time you need
to access a table, and them you update back and all the views from that
point own, have the new changes!

That's what I need to do with c#.

Thanks!

Lester

"sandman" <sa*********@yahoo.com> wrote in message
news:07****************************@phx.gbl...

One way to lock records is to create a column in your
table (call it Status or something). When the user
accesses a record, you set the Status to "in use" (you
define the value) and commit the record back to the
database. When the user is either done or cancels
editing, then the Status is set back to an "available"
status. Timing needs to be managed carefully because
commits (or Update) to the database make all changes
permenent. And the only way another user is going to see
this is to refresh the dataset.

----Original Message-----

Yes,

I think that what I need to do, but I can't find any docs

about how to store

the state in the database!
Do you have some link's that I can read about this,

Thank you a lot!

"codewriter" <co**************@yahoo.com> wrote in message
news:W5*******************@news20.bellglobal.com. ..

You are thinking in the Client-Server mode. This means that you are

caching

information on the client, i.e. storing the state on

the client instead of server. Better way would be to think in a N-tiered application way. In the latter case, it is required to store the state in the database, at least this is what MS recommends. In this case, you have only one source of information, and you do not need to synchronize anything. And you are

right,

every time user makes a search you should go to the

database and get the data.
On top of that, if you want to prevent other users from overwriting, you should implement locking in the database. One way of doing it would be to use a flag field that would indicate that this particular record is being edited by somebody, and whoever tries to overwtite it should get a message that the record is locked. This poses some drawbacks, of course. But it

will

work.

"Lester Moreno" <le**********@covad.com> wrote in

message news:bg**********@sun-news.laserlink.net...
> I think that ADO.NET was design as a web server engine, I have look all > over of a way to Syncronise two users loaded dataset and all I can thing is
> do a fill each time the user try to make a search!
>
> How would you do it?
>
> Thanks!!
>
> "codewriter" <co**************@yahoo.com> wrote in message > news:Vt*******************@news20.bellglobal.com.. .
> > Hi Lester,
> >
> > ADO.NET uses optimistic locking. DataSet is the same as disconnected > > recodset. And I think it is properly designed this way. You do not really
> > want your database being locked when a user opens a dataset. So, I do not
> > think it is a drawback at all, it's by design.
> > If you want to implement locking you should use different approach. > >
> > "Lester Moreno" <le**********@covad.com> wrote in message > > news:bg**********@sun-news.laserlink.net...
> > > Hello all,
> > >
> > >
> > > Up to now C# have been an great experience but I found myself in a

end

> of
> > > the road problem.
> > >
> > > Let say that you have two windows program running

on a local network > area.
> > >
> > > User1 and user2 have the same information in the dataset and user1 makes
> a
> > > change, unless user2 refill all his tables in his dataset he can't

see

> the
> > > new changes made by User1 and it can easily

overwrite them. > > >
> > > Please, if you have some ideas how to make a Sync process please let me
> > > know.
> > >
> > >
> > > Thanks!
> > >
> > >
> >
> >
>
>

.