Curious is it possible to store data / records in web development permanently in browser?
I am developing native apps for iOS, and want to understand how web / javascript works.
Usually when app in native development is downloaded first from App Store and first it is launched, client fetches a lot of data from server, and afterwards at next launches when app is running only record changes moves back and forth. Is it possible these kind of data transfers in web development?
In iOS development Core Data is kind a of a ORM local database, on which JOIN operations can be performed. Is it any local database on web development that provide JOIN like operation?
Yes, there are several mechanism for storing data in browser. Check this out : https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API
There are of course simpler solutions as well, such as localStorage. Websql is interesting too, although it is deprecated.
Of course, there are ORMs for client side storages as well, such as http://couchdb.apache.org
Web SQL provides a local database that can be queried using SQL. But not all web browsers may support this feature.
You can check the support here: http://caniuse.com/#feat=sql-storage
You can also store data locally using local storage, but this method does not use SQL.
Related
I have a Oracle database server hosting data, and I want to build a small app on my local network for people to do light data entry.
Normally we can't query a database from the browser because the browser is client-side and the database is on the server.
But what if the server and website are both hosted on the local network? Would it then be possible? The problem is I don't have a server I'm just making a small website as a file on a shared drive.
But what if the server and website are both hosted on the local network?
This does not change almost anything, maybe it makes things a bit easier when it comes to application security.
Normally we can't query a database from the browser because the browser is client-side and the database is on the server.
That's not true. You can query a database from a browser/client-side. The problem behind such a solution is security of course, because in this case the client would have to know the database credentials, which is why such operations are performed on the server side, but it does not mean that querying database from client-side is not possible.
The conclusion is that if you know the database credentials anyway, it is possible to write a simple application (which will query database from client-side) for yourself. For this you can use OracleDB module.
---EDIT---
I will only emphasize once again that you should not make such an application available anywhere outside for security reasons (availability of database credentials).
However, you can use JavaScript fullstack frameworks like nextjs or sveltekit - they are able to perform some server-side operations and then pass this data to the client. This approach would be much safer.
I'd use Oracle Application Express.
It is installed in Oracle database; lets you develop applications rather quickly (if you know some SQL; even if you don't - use wizards). The only "tool" you need is a web browser. Your users would also need it (the browser), accessing your application via local network and enjoy beautiful application you'll create.
I am creating a web app that allows user to upload some data to the web server. But I want this app to work offline as well , so if network is not availabe it should store the data in local storage and it should push the data to the server when network is available.
Is there a JS library that could simplify this?
The feature you're looking for is the Background Sync API.
You could use workbox-background-sync to make usage easier, including a built-in polyfill for the behavior on browsers that don't support the Background Sync API.
JsStore is a client-side javascript library for performing database operations inside the browser using indexeddb. You can check that.
I understand this is not best practice but I am operating within a limited realm and, as far as I can tell, this is the only solution to this problem.
I am trying to connect to an MS-SQL database both to get data and to put data onto the database. I cannot seem to do it through JavaScript.
ActiveXObject is, from my understanding, now depreciated so that is not working, which eliminates every functional solution that I could find recommended in the past.
Please note: I am not a web developer and I have no access to any of the standard web development tools for this task.
This is the question has been asked multiple times in various forums - Can my client-side Javascript (running in a browser) connect to a database server and fetch data?
The short answer is - not recommended in general, not feasible without breaching security and without using outdated technologies. Let us dig into it.
It is possible to connect to remote database from a browser using outdated technologies
There are two pieces of technologies from Java and .Net worlds - Applet and ActiveX that run on the browser and can communicate to a remote database. The Java Applet is hardly used by anyone nowadays and browsers are stopping to support it. ActiveX is discontinued by Microsoft in their newer browser Edge. So, you have to enforce your target users to use old insecure browsers if you want to go with these options.
Do not use this.
Use databases embedded in the browser and sync with a remote database
You may use the database locally available in the browser and perform all read/write operations. Periodically sync this database with a remote one. Here are the options:
MongoDB and use change stream to sync with a remote MongoDB
PouchDB and sync with a remote CouchDB or even a MySQL database
Use this only for offline storage temporarily in the browser.
The traditional and secure approach to connect to a remote Database
Use a server-side technology to develop an app that your client-side code (Javascript, HTML) talks to. The app may provide RESTful APIs to interact from the client-side. Then the app that is running in a web server connects and interacts with the database. There are plenty of server-side technologies such as Java, PHP, Python, NodeJS (Javascript based), .Net, etc. to develop your server-side app.
Go with this option.
Well javascript is a client side scripting where as your database runs on a server. So firstly you cannot connect to a database for executing any query from client side i.e javascript and also you need to setup a server side service which can connect to the database and execute the query and give you the result at the client side. You can refer any client-server architecture for this on the web.
I'm working on an HTML/JavaScript GUI application that will run on mobile devices (using Cordova) and also as a hosted web page that's accessible from a desktop web browser. I want to give the option to read and store data in a local offline database (SQL database most likely), as well as the option to connect to a web server and read/update data from the server as well.
If anyone has done something similar without having to write the data access routines twice (once for the server side, and once for the client offline storage side), I'd like to get some suggestions.
One solution I am thinking about (which has some unresolved issues still):
I could write the server in any platform (PHP, Java, Js, etc.), but don't want to replicate the data access code for the offline version, so am thinking to do the data access portion in JavaScript--maybe write a node.js server, and use sqlite for local/offline databases (which Cordova supports). I can't figure out how to provide similar local data functionality on a web browser.
The simplest option would be to run a server on the local machine, but I don't think that is easy in Cordova or on a desktop browser.
Check out PouchDB. PouchDB is compatible with CouchDB and is 100% Javascript. You can do some cool offline syncing to online syncing with CouchDB.
Check out https://cloudant.com/blog/pouchdb/ and http://pouchdb.com/faq.html.
I know that for connecting to the database from JavaScript I need to mention the database credentials in plain JavaScript code. Therefore for a online application that would be a huge security risk. But in my case I want to write a small JavaScript application which is stored locally. So the credentials won't be shown to the world but just to the user I give the application, which is acceptable for me.
The motivation behind this is that I want to connect to an online database without a running PHP server, just from a JavaScript embedded in the local page. My goal is to provide an application that can be run by the user without the need for PHP and a server, except the database server. It's similar to a desktop application but running in the browser.
How can I connect from JavaScript to an online MySQL database? All other similar questions I found on Stack Overflow advices the thread starter against this usage for good reason but hadn't answered the question.
I heard that connecting to MySQL from JavaScript would be impossible. But how do, say, Windows 8 Metro Apps written in JavaScript handle that issue?
A backend repeater is always needed. For this issue you can set up a light-weight server that forwards your database accessing request to mysql server using, say node.js.
If you are focussing on a specific web browser, maybe you'll find a workaround. But if you're thinking on a local application independent from the user agent, you should follow the standards to reach a predictable behavior (or at least the best approach). In the W3C standards you have two options for storage:
Web Storage API: you're limited to key-value storage, but is very well supported.
Indexed Database API. I've no experience with it, but it's supported.
If you're not to limit the user context to a restricted machine and user agent, you can start with standard storage solutions as mentioned above and then enhance your app for more advanced browsers (perhaps even with MySQL!), as recommended in Progressive Enhancement