I have an application that works as a Point of sale(POS). It's designed on angular with mssql as the backend. Now its hosted on a server. It is currently working in a restaurant but sometimes since the restaurant has a makeshift internet, It keeps disconnecting etc. Is there a way to make the thing work without internet. At least just to take the order and then when the internet is one it connects to the cloud and updates the DB.
Depending about what you must do. Yes you can install the server in a local machine and you start your angular in your local machine, but you need to use a local machine server if you use POS to take orders. You can create a private connection with a server and connect all subject to this connect. The customers for pay must be connect to internert.
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I am a programmer enthusiast who recently made his first C# and an Android Studio client that uses an “Microsoft SQL Server Management Studio v18.8” database with multiple tables.
Before doing this I had no knowing in SQL programming. My goal is to give the C# client to multiple users and with the Android Studio to verify a final table instruction ( Everything works fine if the devices are in the same network area. example. C# and Android app connected on the same Wi-Fi )
If I switch off the wi-fi on my cellphone and connect it to mobile network I cannot access the database anymore. Upon searching for more information I found out that I need to configure my router for IP-Forwarding with the PORT which is configured in the SQL Server Configuration Manager. ( I edited the exception rules in Firewall setting to allow connections for that port ) Since I am new, my questions are:
Is IP-Forwarding a viable solution for accessing remotely over the internet? Upon searching I understood that it isn’t and my confusion is “How does somebody else access an SQL database remotely ( over the internet ) ?”
Moreover, is accessing remotely over the internet an SQL db viable? If not, what would be the correct approach for a client to INSERT/SELECT something in a SQL server which is located on another network that has an open connection with the internet?
On both clients the string connection is made by giving the server’s IP / PORT, database and Login Credentials. Is there a way to hard code the Password Credential? So that it won’t be a string variable, vulnerable to hacking?
For me is a challenge and I find it fascinating how fun is to manipulate the SQL data and the fact that it works is super impressive.
My 4th question will be off topic, but learning/writing the programs I start thinking: Is an API and an SQL database related somehow? Or at least they work on the same principle?( I have no deep knowledge of what an API is, just basic understanding ) Is this what back-end programming means?
I have some Databases built in Access and I want to be able to view and edit them when I'm not connected to a local server\network.
How can I access with C# to view and edit the Access databases placed on a server without VPN or SMB (which means creating local network). Is it possible to edit it realtime on the server?
This needs to be accessed by more than one people, thus I also want for example block a table if one's already editing it (so here also goes the FTP protocol - to download and edit on the PC and reupload)
I hope I was clear enough and provided enough info, thanks for all helpers!! Enlighten me please :)
We would first have to ask how end users going to run and use the C# program?
Desktop: users would need a network connection to the server. (most likly a VPN).
Web based: users would need a network connection to the WEB SERVER. This could also be a VPN, or could be a web server that is public facing. this would then require logons for security.
If users don't have a network connection, then it not going to matter if this is oracle, MySQL, SQL server or Access. And in fact, if this is web based, then users need to be able to connect to that web server.
So, without some kind of network connection to that server or computer where the data resides, and you eliminated a VPN, then your options are limited.
You can build a web site and place it on a server. However, if users don't have any kind of network connection even in the case of a web site, then I fail to see how you can even suggest using FTP let alone any other kind of connection.
This needs to be accessed by more than one people,
Ok, you need multi-user. However the locking up a whole table on sql server to allow only one user is actually quite difficult.
But, we can leave that you want one user in a given table at one time. (but both Access and a web site would in fact allow multiple users - even editing the same table).
All in all?
Then this suggests the most obvious solution: run a web server, and that would allow any user to connect to the web site, and the web site then can read/talk/use the access database that resides on that server. And this then again means that you don't need any client software installed.
FTP is not a practial solution - since it only works on a whole file.
So, users will require some means to connect to some server. That being the case, then write your C# appliation as web based, and thus no client software will be required, and the only software that interacts with the access file on that server will be the web site.
So, running a web site on that server does seem to be the best option.
So, we heading towards a web solution.
So then software would stay and run 100% on the server side, and thus zero client software would be required other then that of a browser.
I developed a simple Python web server to work with the Access DB via HTTP:
https://github.com/vikilpet/MS-Access-HTTP-Server
Probably this is not an ideal solution for your case but it may be a good starting point.
Scenario: I have a small POS system running in a brick-and-mortar store. The software is running in Windows machines with SQL Server 2008 - 2012 (it varies). There are Android tablets that need to connect to the server in someway to get the data inside SQL Server.
My plan right now is to create some REST Web services using NancyFx and host them as a Windows Service inside the Windows machines. Then the Android tablets will need to connect to the server via HTTP in order to consume the REST API.
I have a problem (perhaps more than one): the network in the brick-and-mortar store is not that reliable and the Wi-Fi signal might decrease for whatever reason.
Question: Is there a way to automatically find the IP or machine name of the server (the one with the REST API) even if these properties change for some reason (unknown network issues or so)?
Yes, the server and the tablets are going to be on the same local network.
it's more of a network problem than programming issue. you must have a DHCP server installed in your LAN. use that to assign an IP to the server with a fixed lease. that way you fix the address of server. clients should preferably connect to that server using its name. since it's a Windows network, name would resolve to the ip address.
that is the simplest solution i can think of
I have a bunch of small desktop applications for which I have a simple database for keeping user data (who uses which app and in which version) etc.
I want the apps to connect to Azure SQL server and update database record when they're started. My apps have the ADO.NET connection string hardcoded in them.
It works fine from my home network and my company guest network - however, the corporate network has got some of the ports disabled, and that apparently includes port 1433. As per Microsoft troubleshooting guide, I tried telnet and failed.
C:\Users\xxx>telnet 65.55.74.144 1433
Connecting To 65.55.74.144...Could not open connection to the host, on port 143
: Connect failed
I cannot connect neither via my applications, nor by SQL Server explorer in Visual Studio.
So, the question is - how can I get around this problem? It is highly doubtful that corporate IT will unlock a port just because I ask, besides I want to keep it as simple, low profile and independent as possible. Or maybe my approach is incorrect from the very beginning and I should do stuff differently?
Cheers
Bartek
You can't.
Make your desktop applications talk to web services instead, over HTTP/HTTPS. Among other things this will also allow a more controlled access (right now anyone can connect to your database and modify the data, since your access credentials are publicly shared with your app).
A side effect of using we services is that 80/443 are almost always opened in all corp firewalls.
We had a requirement to build a ASP.NET 3.5 web application using web forms, WCF, ADO.NET and SQL Server. The users would connect via Internet.
Recently we understood that it is possible that users would often remain disconnected and would have Internet access intermittently.
I need to understand if we can create occasionally connected web application using asp.net 3.5 - what all technologies/features we need to use? Is MS Sync Framework the answer to the problem - is it a viable option to use with web application?
Is windows application the right approach instead of web applications - where the business logic would be run at the client itself, using local SQL Express editions with data then been synced up with Enterprise SQL server at server end when connection is established using replication and/or MS Sync framework. In that case is there a need to use WCF?
Does Silverlight applications help in this context -building paritally connected web apps?
Really appreciate if you can give pointers to how to go about this task of creating .net partially connected apps (not mobile apps)?
It looks to me as if you'll need to store your client data locally when not connected.
If you use wcf you can determine what type of protocol to use according to connectivity without affecting your main code e.g. tcp/ip for LAN, http for internet and msmq for storing up data when disconnected.
If data for transfer is stored up using msmq, as soon as a connection is remade then the data will be passed to your main server.
If you write your wcf, or communications code to run as a service (assuming windows functionality here) then it is up to you whether to retain the asp code or write a new windows app.
edit
Setup MSMQ at both ends, its part of windows setup and can be installed on a client machine, just the same as IIS is, it's on the installation disk but not installed by default.
I wouldn't use it to get web pages, have those available on the local machine, but instead use it to queue up data that MUST get back to the server. Your data access layer should be separated from your GUI layer anyway. I assume that your using the MVC pattern or similar.
I don't know what your application is requried to do but here is the example that I've worked on.
A mobile user who visits clients. He has a replicated copy of a company product database on his laptop. When he visits client sites he may not be able to connect to his company server, but still wants to place client orders. This he does using his laptop based application and database. Order data is queued up in MSMQ on the laptop.
As soon as he is able to connect to his company server MSMQ automatically sends the order data. The server has queued up MSMQ messages of changes to pricing and stock etc. that took place whilst he was disconnected. These are now received and the local database is updated.
The choice of TCP/IP, HTTP or MSMQ all happens seemlessly to the main application, the WCF code copes with the choice.
From what I know, you have two options:
Use Gears (abandoned) or Web Storage to store and sync local data, combined with heavily javascripted web pages that can detect loss of connection and work against the local data store.
Use the Sync Framework with a rich client (WinForms, WPF or possibly Silverlight OOB if it gets supported). The Sync Framework does not require a local installation of a database, instead it uses SQL Server Compact, which is simply a local file.
At this stage using Sync franework with probably rich client seems to be better option. Thanks a lot Guys for taking your time out and trying to answer my queries. I will let you know the technologies used after i manage to deploy the app!