Offline application

[Agnes]

My client got branch in some small city, their network connection is not
stable.
He suggest us to change the application" each time user login the system, it
will automically d/l the master file into his workstation', so, the querry
or searching can be performed in local pc, If the user want to update the
account record, It will connect the sql server (located in data centre) and
update the data.

Does anyone got some idea on it ??
Thanks in advance.
(it seems offline application, but it is not a web form, the application is
run in vb.net)

 

[m.posseth]

well typicly the server should be the computer with the most power so
searching on the server should be much faster as on the client
also how big will this master file be ?? , how about data synchronization to
the client ?? ( user a changes something in the master db , if user b
connected before these changes were applied he will not see this changes )

if we are talking about small amounts of data , ( i.ow. fast method of
fetching the complete updated database ) you could ( again ) choose for a
smart data client aproach
create a trigger in your database that will change a value( guid ) when a
update / insert / delete takes place on the table on startup retrieve all
data and now poll the database once in while to see if there was a
alteration on the master table ( so you know you should retrieve the new
dataset )

if you are so lucky that you use SQL 2000 or better SQL 2005 you may
investigate notification services ,,,, ( with this it is possible for your
app to subscribe to a dataset for notifications on that dataset , basicly a
callback event to your app takes place whenever such an event occurs )

regards

Michel Posseth [MCP]

 

[Michel van den Berg]

Dear Agnes,

I think what you need is called transactions. Transactions are database
actions where the action completely fails or completely succeeds.
If it will completely fail then you don't need to worry as all is reverted
back to the state before the action. This way your database will not become
corrupt.
However, having an unstable network connection, can mean that your
transactions will fail often. I don't think you can do anything to prevent
your application to inform its users that the transaction failed (eg with a
msgbox or something). If you where to build an advanced checking system to
see if your connection is still alive, the transaction could still fail, as
the network connection can die between checking and the transaction. IMO,
you should just try and do the transactions and if it fails, inform the user
and let them try again.

However, there are more people on this forum which may have a better
suggestion, so stick around and here them too!

Michel van den Berg

 

[m.posseth]

Maybe they should better spent there money in stabilizing there network
connection first

just my thoughts

 

[Cor Ligthert [MVP]]

Michel,

Maybe they should better spent there money in stabilizing there network
connection first

In China, I thought that they were quiet busy there?

Cor

 

[Cor Ligthert [MVP]]

Agnes,

Probably is this the horse behind the car. To get that data you need a
stable connection because it is probably much huger than you need now.

Otherwise you would have to do it as if the workstation is a PDA, in fact is
that where .Net is made for, and create dataset files as complete as is
needed (and write those than intermidiate to disk). Not that it is much
work, however probably a complete different approach as you have designed
now.

(You cannot do a select on that dataset, you need to process it as a
dataset)

Just my thought,

Cor