I'm working on a project that can take data from a Weintek HMI, put them on a webserver and then send them to an application that I created on android studio.
I've found firebase that can help me in this task.
In easybuilder that works with my hmi, I can create a mysql database that can store the data.
The problem is how can I update automatically firebase database with mysql database with an interval of time in order to access them on the android app.
If there is no solution with mysql, can someone suggest other method to extract the data and use some web server to sync it with the android app?
I don't know your specific need, in terms of data volume or application, but as a workaround, maybe this can help you:
I usually apply MQTT, which many Weintek HMIs have, to send telemetry data, and then use NodeRed to process and redirect the data to a database, email, SMS, Telegram, CSV, TXT... depending on the need , which in your case could be Firebase (I never used it).
It works great for me as I don't have to worry about HMI limitations.
The problem is the reliability of the data, in terms of confirming that when the HMI sends, the server listens and writes, but there are certainly ways to deal with this, and the fact that you need to have a server with NodeRed running.
If you have never done so, in Weintek HMIs you can send the MQTT payload cyclically using macros easily.
Related
I'm having a problem with my re-frame application. I can't figure out how to connect it to a local database on my machine.
In other applications I've written, I've had to add the database specifications (username, password etc) into profiles.clj. Should I create profiles.clj and add the location of my database there? And does this mean I have to update the project.clj as well?
Finally, do the queries to the database, such as GET and POST requests, go in db.cljs.
I apologise if these questions are trivial but after reading the documentation several times I am still a little confused
re-frame is a framework for building client-side web applications. You won't be able to do generic database queries as most databases don't support direct access from a browser.
I'm having a problem with my re-frame application. I can't figure out how to connect it to a local database on my machine.
You probably need to create a middle API tier that accepts REST requests from re-frame, and queries the database, returning JSON back to the client.
Finally, do the queries to the database, such as GET and POST requests, go in db.cljs
Those are probably queries to your API tier? They can live anywhere that you would like.
One thing to clarify: re-frame has an app-db that it uses and refers to. This is a client-side database of local state that lives in your application. It doesn't have a connection to the backend, at least not without you writing more code for it. It sounds like you might be confusing these?
I'm struggling to find a solution to what I thought would be a common requirement so I'm hoping someone can help me with some pointers on what to search for/areas to explore.
Background
I'm building an iOS mobile app. I'm storing data locally using realm.io. The app is preinstalled with a snapshot of the content of a Wordpress mySQL database (it uses custom types). The content of the WP database is only written via the Wordpress install, the mobile app cannot write data.
Objective
So, I want to be able to check for changes since a given date (whenever the local database was last updated) and send the changed records to the mobile app (via the wp JSON api?).
I think I can fetch "posts since a date" but I need a full list of all create, update and delete operations since a given date.
Since the app is read-only I thought this type of one-way sync would be pretty straight forward but I can't find a common solution.
Any ideas to point me in the right direction would be great. Obviously, if anyone has any experience of doing this sort if thing with realm.io then that would be amazing :-)
Realm doesn't support yet any sort of synchronization mechanism across different files. We have an issue about that though, but you're likely searching rather for a solution in the immediate future.
Update: Realm launched the Realm Mobile Platform. This offers synchronization functionalities and would greatly simplify the solution for this use case.
You could use e.g. the server-side Node.js binding to pull new data from your MySQL Wordpress installation and push them to a global Realm served by the Realm Object Server. This can be read-only synchronized from the mobile apps, which would automatically receive the deltas and provide updated data to your users.
Whatever mechanism you come up yourself though in the meantime, it would require that you have read-write access from your iOS application to the realm database, so that you can update it with new data.
Pushing changed records as you describe is likely not going to work.
Apple's Push Notification service (APNS), which is the only back communication channel that works when your app is in the background or suspended, allows you to send very small payloads. You would use that to signalize your iOS app, that something changed on the server-side and there is new data to load. You would then initiate a request to a JSON-based API, wait for the response, map the returned JSON to Realm objects and store them in your database.
You want probably read more in the "Downloading Content in the Background" section of background execution chapter in the official App Programming Guides for iOS.
While pre-seeding the database from the app bundle seems like a nice idea, because the user wouldn't need to wait initially after downloading the app, that will enlarge the app itself with data, which might become in the future completely irrelevant.
For my Windows phone project (it's a Universal app), I have a set up that has a country and a phone number in one of the page. There are about 7 other pages that requests the user for additional information. But for starters, let's just stick with the first one, that asks for the country and the phone number.
I read through a million posts in Stackoverflow and other websites alike, to know what database system is best to implement with the sort of app I am going to be developing, or hoping to develop.
Here're my findings:
Azure SQL: I have an Azure account and I can use the Azure SQL service to store the user-input data directly to the database (when the app goes live), or while in the testing phase. But I got to know that feature isn't really working well as windows phone cannot readily update the data to Azure SQL, on realtime basis. Is it so?
MySQL: I thought I'd create a local MySQL database, for testing purposes, so as I input the data (in the emulator perhaps), the database saves it. I am unsure how I can implement this. I can't find any article I can read that can help me with this. There are with ASP.net, but it isn't what I am going to be using.
SQLite: I know for a fact the data can be stored locally, by using SQLite, but I could like to know if the locally stored data can be later updated on a server-side machine (i'd prefer Azure SQL, but MySQL is also OK with me). If it can be, i wouldn't mind settling with it. If it can't, what can I do?
It all boils down to this: What's the easiest way to store data entered in a textbox (lol, yeah!) to a database (locally or server-side)?
Your efforts to help me will be greatly appreciated!
Thanks!
You can stay on Azure SQL if you have an account.
It works fine and it updates database on the go (sends json as far as I remember), so you shouldn't worry about data being stored in a cloud. Moreover, it is super-easy to use it for your needs (store data from textbox).
Azure SQL will get your bootstrap the fastest for your application. There is no need to deploy MySQL or SQLite and managing your DB. There should not be any concern about updating the DB live from the app.
We plan to use a MySQL database as the backend for our (Java or Ruby on Rails) based web application. After completing the web application, we want to port the application to iOS and Android.
We want to be able to run the application in "native" mode - that is, if a network connection is not available to the smart-phone, the system should be able to store the data locally, and sync with the backend when the network connection becomes available.
The best kind of framework for this kind of syncing is a library/framework such as Parse.com.
The question to which we want an answer is: is it possible to exchange data between the web application data stored in MySQL, and the Parse.com data which is stored in a proprietary format on the Parse servers?
Answer to your question: It is indeed possible, but syncing data is an advanced topic.
However, you also state that you want to access the parse data when offline. As I understand it, you want Parse to handle the offline state, and then sync to MySQL when connection is back up. Parse does not offer functionality to store data offline, other than caching requests. You probably need another service for your specific needs.
I might have misunderstood the use case. If so, my alternate understanding would be that ALL data for the smart phones will be handled by parse: both offline and online, with syncing. The answer is still: parse does not offer this kind of functionality.
I would like to make some AIR application which would be used for tracking jobs inside a company.
The idea is to create some database which will handle all the data and, when other users form other computers modify data, it is always saved on that same 'server'.
So, more than one user can edit same database, and it would be great if all the data is constantly 'refreshed' (if one user edits and saves data, on other users' computer data is instantly updated). Application would be used only in local network.
I have some data in Excel, so I also wonder if AIR can handle it somehow? Or is it better to re-structure the whole db?
So, which kind of db should I use? I've read that AIR likes SQLite very much, which would be good because I work with MySQL...
Is AIR (in combination with SQLite) able to handle ALL my needs (working over network, sharing same db, refreshing data, creating server/client applications or something, etc.)?
Thank you very much for any thoughts!
m.
There's no restrictions on what database you can use. My advice would be to create an interface in PHP or ASP or whatever language you prefer (since the Database is on a server elsewhere, you'll need some sort of network connectivity anyway), and send all requests and modifications through that.