SQL Server Synchronization Of Occasionally Connected App?
Mar 11, 2010
Beginning development with SQL Server 2008, VB - Visual Studio 2008 on an application that will deploy laptops remotely for 6 months or more. The laptops will have no network or internet connection. There is a requirement to sync DB changes via shipment of USB flash drives.
The remote app will have a subset of the home database data. Some tables need to be synced bi-directionally, some uni-directionally. When the laptop comes home, it will do one last sync, the local DB will be wiped, and it will connect to the home DB.
Being that there are some identity key columns and the remote is only a subset of the the home, I am not sure that SQL Server replication or synchronization functions can be utilized.
Should I Create SQL Server Compact DB's on the remote system when it is deployed and do a table by table compare (in code) to another compact DB created on the flash drive when a sync is needed?
I'm trying to teach myself how to create an Occasionally Connected Application. I want to create a simple app (like a survey) that will store all the data on a server but have the front end run on the users computer. The users computer may or may not be connected to a server when the data is entered (they may be collecting data in the field).
Program does 3 things:
1. Shows data from database (ie, displays survey data stored on server)
2. Saves data to database (ie, new entries or changes to old entries)
3. Has a background thread that checks for network connection
a. If no connection exists:
i. Gets data, to show, from local database
ii. Saves data to local database
b. If connections exists:
i. Sync local database with network database
ii. To read data: Gets data to show from local database which is now synced with network)
iii. To save changes/new entry: Save changes to local database then sync changes with network, then send update call to anyone else running this app on a different computer so they will get the same changes?
I get this error while im following the "Walkthrough Creating an Occasionally Connected Application" [URL]
Im already in the " To configure tables for local caching" > step 4.
Then when trying to connect this error pops.
"Failed to sync database" <a href="http://tinypic.com" target="_blank"><img src="http://i45.tinypic.com/ur3fq.jpg" border="0" alt="Image and video hosting by TinyPic"></a>
My first post here in vb forums. I'm new to sockets programming since I migrated from Winsock and I learn a lot from Atheist. using his code, I can't access the messageReceived() every time a client sends a message on the server. but then I put a code to catch the message on sub doRead() and I can retrieve the message. My problem now is how can I determine if a client is still connected to the server or not so I can delete it on the ConnectedClient ?
[Code]...
Note: the server runs on Win7 x64 ultimate and the clients are laptops on win7 x86. I read a comment that the server should be having a static IP address, but when did it together with the clients, It still doesn't work. I am just using a switch for the network.
I have a MDI App. connected to SQL Server 2005 database via ODBC, and there are two forms in MDI Parent form, called form1 & form2, both of the forms are contain a datagrid.
The problem that I have when try to save data from datagrid, enven thus, it says the data saved, but there are no data have been saved,and this is an intermittent problem.
I need an article tutorial link or code on how to prind a datagridview connected to an sql server table and it's records with prindocument and maybe gdi+(?).
I'm trying to make a client and a server connected in vb 2010. how to make a client and server connected? There is only vb2008 in the codebank and if my vb2010 tries to convert it to vb 2010 it will error.
I am Using Visual Basic 2010. I want to check My Connection Status. Connected or not in Remote Server Connection (SQL Server 2008 R2). How To Check Connection Status..?
How would i go about seting up a local database to store data so it can be used offline then to sync up with SQL server 2008 r2. i've got to the point of having a test project with a local DB that stores the data and a test SQL server but know idea how to set it up to sync with between databases.
I need to check if my client is connected to the server by starting a new thread. So in short I need a way to know if the client is still connected to the server.
I have a simple tcp server listening for clients. I use a mud client to test if it's working. The mud client says that it's connected to 127.0.0.1, but the server doesn't show the msgbox that a client has connected.[code]
I have 2 clients connected via a server program.When 1 client hits an arrow key, a picturebox moves on client1 and on client2.Before adding this network functionality, the picturebox on client1 moved fast with each click.Now, there is a delay of like 2-3 seconds.I know the code isn't optimal, but i'm not a networking wizard.What i'm doing is when pressing a key on client 1, it passes a text to a textbox in client 2 which then has the picturebox move in client 2 depending on the text.The slowdown occurs on client 1, which is odd because the picturebox isn't directly connected to the network code.[code]
On my program I am trying to make a ToolStripStatusLabel's text change to "connected" if connected to a network and if not connected to a network change the text to " Not Connected" then I don't know how to display a image if connected to a network or not connected. So if the computer is connected to a network I have a image that I would like to be displayed next to the ToolStripStatusLabel. And if not connected to a network, can the program display a different image? I tried this:
I want to carry out bidirectional synchronization.I have implemented the code and procedures in the walkthrough however i have nearly a hundred forms and more than 50 tables how do i go about that
I have a question regarding the synchronization in multi threading.
I have a function called send which i am calling in a for loop for every data row.
This function creates threads to send emails to different people.
Public Sub send(ByVal Conn As Data.DataRow, ByVal job As Data.DataRow) MyThread = New Thread(AddressOf Me.start) MyThread.Start() End Sub
But every thread created is writing to a log file at different points of time. So, there are very high chances that 2 threads write to the same file at the same time. So, do i need to use any kind of synchronization mechanisms here ? or is it fine without them ?
I want to know how dropBox is able to synchronize the large data files without replacing or re-uploading the files again to the dropbox server Example: an encrypted zip archive Suppose I've a 1GB encrypted zip archive file Fully synchronized on my computer and on the dropbox servers. On my computer I added to that zip archive file a file of size about 5MB then saved the file on my computer. Dropbox is able to synchronize zip archive file without re-uploading the whole file again instead it just update it with the small change I've done. Also TrueCrypt containers works in that manner.
MainForm having a few buttons, VolForm is inheriting MainForm. I can see this perfectly in the designer.VolForm itself contains a trackbar. Now have 2 forms. Form1 and Form2 both inherit VolForm. If I change the trackbar from Form1, and then show Form2, the trackbar is not having the same value. Is there any way to keep this trackbar the same in every form that inherits VolForm?
I was trying to work out the best method of synchronising an update of files via vb.net. I want to automatically update some files in a few folders from an FTP site to a local drive. This would ideally be the same folder structure, but on a specified local folder. I have looked at the FTP methods in .net and am able to transfer individual files successfully, but wondered if there was an elegant method to collecting the entire folder from the FTP and it's contents to be re-created locally. I have established the reading of an XML via linq from the ftp to establish an update single and decide whether the local machine is up-to-date or not, it's just the transfer of the folders that I'm stuck on as it's different to using a IO method.
I need to develop a synchronization mechanism for 2 or more containers tha contains objects (generic classes) In each container the origin of the object can be:
1) Created New
2) Imported
3) Recovered from the bin (they have been previously deleted)
The main problem that I am facing is this one If One object has been deleted in Container A it should be Deleted in Container B as well during synchronization If one object has been DELETED in Container A (1 hour ago ) and teh same object has been DELETED and RECOVERED in Container B ( 1 hour and 1 second ago) what should i do? keeping in consideration that between the 2 computer the time is surely not identical?
I am trying to test if my synchronization mechanism is set well and so for debug purposes, inserting a deliberate deadlock as under
mtx.waitone(-1) mtx.waitone(-1)
but when i step through the code in the debugger, it runs fine without getting stuck here. I am sure there is no other thread doing a release on the mutex mtx
How do I create a Login Verification routine (Login Form) in vb.net . i have an windows application with login form contain user name , password , ok button and cancel button .
as this one:
Imports System.Data.OleDb Public Class LoginForm1 ' OK button
[Code].....
but i want to run my application from desktop and will get confirmation if the user name and password correct by checking them in MS Access Database in the server.
so the the application in the desktop and the tabel of user name and password in the server.
I don't know if my question is sql server related or vb.net or both. so I will ask it here. Let say I have 3 sql servers with replication among them connected together by vpn. let say i have a customer C1 exist on first server S1 and his account is 1000$ which is the same on second server S2 on S1 they enter a new receipt, so the customer C1 on S1 balance became 1100$ while it still 1000$ on S2, and it need 1-2 min for the replication to finished if during this 1-2 min, S2 is entering invoice, C1 balance will show 1000$ while it is actually 1100$ (because the replication did not finished yet) My first idea is to make sql query getting the customer balance from 3 servers and compare them. How I can tell that the customer account are not the same on both servers or check if the replication is finished for that table holding the customer balance?
I have a MDI parent that opens another form like this:
Dim frm As New Form1 frm.ShowDialog(Me)
That form has a button that, when clicked, does this:
CreateObject("Shell.Application").ToggleDesktop()
The button operates as expected (showing the desktop) most of the time but occasionally does not minimize the MDI parent. All the other windows, including the form above get minimized every time.
I have a Windows Form custom control that displays alerts on a customer record. The control uses an Infragistics 9.1 UltraWinGrid to display these alerts, which is filled from a dataset populated by a business object. Some users are having issues viewing these alerts; the grid will be completely blank, like the fields were hidden for some reason. This sample code shows how the grid is populated:
Private Sub InquiryCallbackAlertList(ByVal sender As Object, ByVal e As FunctionRequestEventArgs) Try 'Code to populate the dataset mdslist AlertsGrid.Visible = True [Code] .....
I have not had any success finding anything out about this problem. I did add some trace logic to check the 'HiddenResolved' property on the grid rows and am waiting to find out the results of that. Is there anything else that could be causing this grid to only be hidden for some users and not for others, and also could anything else be causing this only to happen occasionally?
I am developing Windows Forms Application SRacq10 in VS2010 in VB.Net. It provides a WCF duplex service and obtains real time financial market data using COM object TWS (Trader Work Station) provided by Interactive Brokers, Inc. SRacq10 works well most of the time. Occasionally, it crashes; I have not been able to observe a pattern of circumstances when it crashes. When I try to add debug to a text file, I can never make it crash; that's not an acceptable solution in the long run. Here is the fault information when running the debug version outside of VS2010:
Event Viewer: Faulting application name: SRacq10.exe, version: 1.0.0.0, time stamp: 0x4de7a42c Faulting module name: MSVCR80.dll, version: 8.0.50727.4940, time stamp: 0x4ca2b271
We have a vb application with many forms that contain a "lookup" button that has an icon called find.ico. Once in a while, a user will open one of these forms and get the below error but not every time. Has anyone else run into a similar situation? Since it is not consistent, it's been very difficult to track down.
