The machine I'm trying to access is an industrial PC that serves as the interface for some PLC-automated equipment. The computer creates a data record (an .mdb database) of the various machine settings so that they can be reviewed later if desired. I've created an application in Visual Basic 2010 to display and sort that information once it's been copied from the machine to someone's laptop.
What I'd like to do, though, is allow the user to access the database from their laptop over the network; each PC has a static IP address on the customer's LAN. Currently, we can use Teamviewer to transfer files, but I'd like to include that ability in my data viewing application. Without changing any settings on the industrial PC (i.e. leaving the network file sharing alone, and avoiding installing any sort of SQL server software), how can I access this information? The database files can get pretty large (40+ mb) so I'm trying to avoid any sort of FTP transfer, which would undoubtedly take forever.
The database is already set up on an ODBC connection (which is how the pc stores the PLC information in the database), and I suspect that this may be the key, but between my lack of any thorough understanding regarding networking and the internet's general distrust of ODBC (well earned, from what I've seen so far), I'm having a hard time finding any useful information.
If anyone could point me towards some useful tutorials, or give me a good place to start, I'd appreciate it.
I think you are out of luck. Think about it, if you could access the file, without sharing it, wouldn't that be a serious security problem?
What you can do: Use the always existing share \host\c$ to access the file. For that you'll need administrative privileges for the host.
But be aware: Even if this "works", it introduces problems:
It will be slow, because you are essentially copying 40MB over the wire over and over again
If you are not carefull, you might lock the *.mdb file while accessing it. Access Databases are not really meant to be accessed by multiple users/processes. That didn't prevented Microsoft to try to fake it. Todo so, a *.ldb (L as in Lock) file will be created, to signal other processes the file is locked.
Tldr: Don't do it.
Related
First of all, I don't mean version control such as git.
I do use git locally but, I'm trying to determine the best way to do back-ups of source code (as well as other app assets) in case of hardware failure or such.
I was thinking I could set up a script to tar my project folders, and encrypt them with gpg. I would then save the encrypted tar to external hard drives and to 1 or more off-site locations using a service such as amazon drive or dropbox.
Currently, I'm a sole developer so my thinking was that this method should be okay. But I wanted to get some input to make sure I'm doing this the best/most reliable way possible.
If there is a better approach to this that may be more applicable to small teams, then please let me know, as I'm more than happy to do the extra work implementing the approach.
There are much of ways of doing that.
But, if you always work local and you need a simple way of doing that, you may take a look at run scripts if some specific usb device is plugged in.
Meaning that a simple backup script with tar would run if you plug in your specific backup hdd.
Take a look at udev rules in linux.
udev is a generic device manager running as a daemon on a Linux system and listening (via a netlink socket) to uevents the kernel sends out if a new device is initialized or a device is removed from the system. The udev package comes with an extensive set of rules that match against exported values of the event and properties of the discovered device. A matching rule will possibly name and create a device node and run configured programs to set up and configure the device.
Take a look at these posts:
https://unix.stackexchange.com/questions/65891/how-to-execute-a-shellscript-when-i-plug-in-a-usb-device
&
https://askubuntu.com/questions/401390/running-a-script-on-connecting-usb-device
If you plan to go further, to extend the team or even to keep your code for a while in other words, if you want to be professional, I would go with a scalable and reliable tool designed for this: use a real backup and restore tool and don't use scripts. A lot of people, small (and even not so small) companies are doing it and they end up in trouble: maintenance, scalabolity, update, and so on.
There are plenty of backup & restore tools for different purposes and/or platforms, prices and so on. https://en.wikipedia.org/wiki/List_of_backup_software would be a good start :)
Cheers
Werlan
I created a time recording program in vb.net with a sql-server as backend. User can send there time entries into the database (i used typed datasets functionality) and send different queries to get overviews over there working time.
My plan was to put that exe in a folder in our network and let the user make a link on their desktops. Every user writes into the same table but can only see his own entries so there is no possibility that two user manipulate the same dataset.
During my research i found a warning that "write contentions between the different users" can be occur. Is that so in my case?
Has anyone experience with "many user using the same exe" and where that is using datasets and could give me an advice whether it is working or what i should do instead?
SQL Server will handle all of your multi-user DB access concerns.
Multiple users accessing the same exe from a network location can work but it's kind of a hack. Let's say you wanted to update that exe with a few bug fixes. You would have to ensure that all users close the application before you could release the update. To answer you question though, the application will be isolated to each user running it. You won't have any contention issues when it comes to CRUD operations on the database due to the network deployment.
You might consider something other than a copy/paste style publishing of your application. Visual Studio has a few simple tools you can use to publish your application to a central location using ClickOnce deployment.
http://msdn.microsoft.com/en-us/library/31kztyey(v=vs.110).aspx
My solution was to add a simple shutdown-timer in the form, which alerts users to saving their data before the program close att 4 AM.
If i need to upgrade, i just replace the .exe on the network.
Ugly and dirty, yes... but worked like a charm for the past 2 years.
good luck!
I have read several articles about creating a Sharepoint Developer VM. They all say to "sysprep" them. Why (exactly) must the sysprep be done? What kind of problems (and why) will we run into if we don't sysprep them?
(I suppose what I am asking is, what would be the difference in doing "sysprep" and just bringing up the VM, changing its Name/IP, reboot then install SP?)
I've had success in the past with just copying Hyper-V vhd's as a method of cloning VM's - however, I now use sysprep when cloning any of my machines as it's been mentioned as a best practice in many places. And, it does some nice things like allowing you to cleaning up a bunch of stuff that I don't want to duplicate and letting me choose a new name for the machine on boot. From MS Sysprep Technical Reference:
Sysprep prepares a computer for disk
imaging or delivery to a customer by
configuring the computer to create a
new computer security identifier (SID)
when the computer is restarted. In
addition, Sysprep cleans up user- and
computer-specific settings and data
that must not be copied to a
destination computer.
And you may want to read Russinovich's post on The Machine SID Duplication Myth (and Why Sysprep Matters) for more good explanation of how SIDs work and the very last paragraph has another reason for going this route:
Note that Sysprep resets other
machine-specific state that, if
duplicated, can cause problems for
certain applications like Windows
Server Update Services (WSUS), so
Microsoft’s support policy will still
require cloned systems to be made
unique with Sysprep.
Good luck!
I've got an Access 2007 database that I developed which connects to SQL Server for the actual data storage. I used the Package Solution Wizard to create a distributable installer which included access runtime (with an ACCDE file) which I went around and installed on 15 or so PCs. Anyway, my question is, what is the best way to distribute updates to this database? Right now I'd need to go around and remove and reinstall. That's not a problem... I was just wondering if there was another way.
I've tried leaving the front end on a network share but it seems that most people suggest storing the front-end on the local machine, which makes sense. The problems I've run into when I leave it on a network share (at least with Access 2003 mdbs) is that I find myself needing to compact and repair often and I also have to kill the open sessions (user's who have the file open) when upgrading. I would imagine it could also hypothetically create an unnecessary bottleneck if the user was not on the local network.
Automating front-end distribution is trivial. It's a problem that has been solved repeatedly. Tony Toews's http://autofeupdater.com is one such solution that is extremely easy to implement and completely transparent to the end user.
We developed a vbscript 'launcher' for our access apps. That is what is linked to on the start menu of user's pcs and it does the following.
It checks a version.txt file located on a network share to see whether it contains different text to a locally stored copy
If the text is different it copies the access mdb and the new version.txt to the user's hard drive.
Finally it runs the mdb in access
In order to distribute an update to the user's pc all that is required is to change the text in version.txt on the network share.
Perhaps you can implement something similar to this
Make a batch file on the server (network drive).
Create a shortcut link to that batch file.
Copy the shortcut to User's Desktop.
When user double-clicks on shortcut, it will copy a fresh copy from network to local.
Replace old database.adp on the server drive when you update a new version.
Each user gets a copy of database.adp on their machine.
Remove Security warning when opening file from network share is here.
Batch File
#ECHO OFF
REM copy from network drive to local
xcopy "Your_Network_Drive\database.adp" "C:\User\database.adp" /Y /R /F
REM call your database file - Access 2007
"C:\Program Files\Microsoft Office\Office12\MSAccess.EXE" "C:\User\database.adp"
This is a very old post and I used the autofeupdater until it stopped working so I wrote one of my own and it has evolved over the last few years into something that I have used with many clients. It's so simple to use and there is no interface. Just an EXE and a very simple config file.
Please check it out here. I can also help with custom solutions if none of the configurations work for your needs. http://www.dafran.ca/MS-Access-Front-End-Loader.aspx
After trying all of the solutions above (not exactly these solutions but these are the common suggestions in the Access community), I developed a system entirely within Access using VBA that allows an admin DB to create and publish objects to client DBs without the need for user intervention or management of multiple DB files.
This approach has several benefits:
1. It simplifies the development process by having a dedicated environment (admin DB) for development and testing totally separate from the client DBs.
2. It simplifies the update/distribution process by allowing a developer to push out updates in real time that client DBs can implement in the background, without involving users. Can also allow devs to roll back to previous versions if desired.
3. It could be used as a kind of change management system within Access for developers who want to commit multiple changes to objects and modules and retain past changes.
4. It allows for easier user access control by allowing an admin to easily assign certain objects to specific users/roles without needing to maintain multiple versions of the DB.
I will hopefully post the code to GitHub soon, I just have to get clearance from my workplace to release it. I will edit this post to include the link when I have.
We have usually kept the Access front ends on network drives, and just put up with the need to compact and repair on a regular basis. You will probably find you need to do that even when they are installed locally, anyway.
If you must have it installed locally, there are various tools which will enable you to "push out" software updates, and the guys over on ServerFault would have more information on those. Assuming such tools aren't available, the only other option I can think of is to write a small loader program that checks the local .MDB against a master copy on the server, and re-copies it across if they are different, before then launching the MDB.
I have a mdb file hosted on my site http://www.simplyfy.co.in/db/dbfile.mdb. I am developing an application which will be running on multiple machines and will contact the mdb file via internet. I am not sure how do i go about it as building the connection string for an online connection. Any help?
You do not - not at all, not even a little bit, want to expose a .MDB file directly over the internet. You really, really do not want to do this.
There are two reasons and I'll start with second, even if it works - and since it needs to be able to create a .ldb file if its not read only I'm not sure it will - it is liable to be horribly slow. Multi-user MDB can be bad enough over a local network.
The other reason is security, assuming it works at all you're going to really struggle to make this even vaguely safe.
Broadly speaking what you need to do is to create a web service that runs on your site that provides an secured API that your client applications can use to access your database - this gives you two benefits: 1) its much more secure (you're not exposing webspace with write permissions) and 2) it gives you the ability to change the back end data store if required without affecting the clients. There are various possibilities for implementing this but it will depend on the tools you have/are comfortable with.
I think it is possible to access the same way that access a local file, simply using the URL as Data Source. That is, the connection string looks like:
Provider=Microsoft.Jet.OLEDB.4.0;User ID=...;Data Source=http://www.simplyfy.co.in/db/dbfile.mdb;Mode=..., etc
HTH