I am a beginner and this is my first full-stack web development project and I have completed the front-end part and created the related tables using MySQL... and now I want to link the tables to front-end using nodejs. How do I proceed further?? Is it proper to use workbench in the first place for a full-stack project?? Please guide me.
SQL Workbench is just an IDE for mySQL so thats fine for building out your DB, setting permissions etc.
Your question is not one that is simple to answer, simply because the steps in creating, setting up a full web app is not that simple to explain..
There are few things you will need to do to hook this up
Ensure you have a mySQL middleware installed
Ensure you have the routes created
Use a templating engine like EJS
Once you have the basic flow working ( meaning you can hit your page and it returns the correct page ) you will want to then hook into the DB before sending the response object back to the browser. A typical flow would be, on your 'get' response, you would perform the mysql 'select'
This should be promis based but will depend on the actual package you install, I don't use mysql but a postgres command is something like
query.pool("SELECT is, name, des from table where id = '10' ").then(results => {
//put in your response code here to send back to the page
}).catch( e => {console.error(e)})
The response code portion is where you would send things back to the page, in an ejs template would then be able to access the response and display the data.
I know, this is a bit light on full explanations and that is because the proper response would be huge!
Judging by the question I would guess you are a bit new to node / DB etc ( sorry if you are not ) I think what may be very helpful is to watch a few youtube videos on setting up Node and EJS ( or any templating engine for that matter )
That should give you the basic understanding and setup of the project.
Related
I'am currently playing around with the Couchbase Sync-Gateway and have built a demo app.
What is the intended behavior if a user logs in with the same username on a different device (which has an empty database) or if he deleted the local database?
I'am expecting that all the data from the server should get synced back to the clients.
Is this correct?
My problem is that if i'am deleting the database or login from a different device, nothing will get synced.
Ok i figured it out and it's exactly how i thought it would be.
If i log in from a different device i get all the data synced automatically.
My problem was the missing sync function. I thought it will use a default and route all documents to the public channel automatically.
I'am now using the following simple sync-function:
"sync": `function (doc, oldDoc) {
channel('!');
access('demo#example.com', '*');
}`
This will simply route all documents to the public channel and grant my demo-user access to it.
I think this shouldn't be used in production but it's a good starting point for playing around.
Now everything is working fine.
Edit: I've now found the missing info:
https://docs.couchbase.com/sync-gateway/current/configuration-properties.html#databases-this_db-sync
If you don't supply a sync function, Sync Gateway uses the following default sync function
...
The channels property is an array of strings that contains the names of the channels to which the document belongs. If you do not include a channels property in a document, the document does not appear in any channels.
I'm new to using Svelte and would like to create a ordering website using Svelte. I know that I will need a database to keep track of the order, customer name, price etc. I have used MySQL before but I haven't learned how to connect a database to a website.
Is there a specific database that you can use if you are using Svelte?
Or is there a way to connect MySQL to Svelte?
I have searched about this on Youtube and Google but I'm not sure if it's different if you are using Svelte so I wanted to make sure.
Note: I have not started this project yet so I do not have any code to show I just want to know how you can connect a database if you're using Svelte.
Svelte is a front end javascript framework that run on the browser.
Traditionally, in order to use databases like mysql from a front end project such as svelte, (that contains only html,css and js), you would have to do it with a separate backend project. You can then communicate the svelte app and the backend project with the help of REST api. The same applies to other other front end libraries/frameworks like react, angular vue etc.
There are still so many ways to achieve the result. Since you are focusing on Svelte here are few things options
1 Sapper
Sapper is an application framework powered by svelte. You can also write backend code using express or polka so that you can connect to database of your choice (mysql / mongodb)
2 User Server less database
If you want you app simple and just focus on svelte app, you can use cloud based databases such as firebase. Svelte can directly talk to them via their javascript SDK.
3 monolithic architecture
To connect with mysql in the backend, you would need to use one serverside application programming language such as nodejs (express) php or python or whatever you are familiar with. Then use can embed svelte app or use api to pass data to the svelte app.
I can make an example with mongodb
You have to install the library
npm install mongodb
or add in package.json
Then you have to make a connection file that you have to call everytime you need to use the db
const mongo = require("mongodb");
let client = null;
let db = null;
export async function init() {
if(!client) {
client = await mongo.MongoClient.connect("mongodb://localhost");
db = client.db("name-of-your-db");
}
return { client, db }
}
for a complete example with insert you can see this video
https://www.youtube.com/watch?v=Mey2KZDog_A
You can use pouchdb, which gives you direct access to the indexedDB in the browser. No backend needed for this.
The client-pouchdb can then be replicated/synced with a remote couchdb. This can all be done inside you svelte-app from the client-side.
It is pretty easy to setup.
var db = new PouchDB('dbname');
db.put({
_id: 'dave#gmail.com',
name: 'David',
age: 69
});
db.changes().on('change', function() {
console.log('Ch-Ch-Changes');
});
db.replicate.to('http://example.com/mydb');
more on pouchdb.com
Also the client can save the data offline first and later connect to a remote database.
As i get question mostly about connection to backend, not a database. It is pity, but svelte app template has no way to connect backend "in box".
What about me, i'm using express middleware in front of rollup server. In this case you able to proxy some requests to backend server. Check code below
const proxy = require('express-http-proxy');
const app = require('express')();
app.use('/data/', proxy(
'http://backend/data',
{
proxyReqPathResolver: req => {
return '/data'+ req.url;
}
}
)
);
app.use('/', proxy('http://127.0.0.1:5000'));
app.listen(5001);
This script opend 5001 port where you have /data/ url proxied to backend server. And 5000 port still available from rollup server. So at http://localhost:5001/ you have svelte intance, connected to backend vi /data/ url, here you can send requests for fetching some data from database.
hi guys how can i get information like how many number of class files which will be executed from particular test class from sonarqube database,my sonarqube database is resided in MySQL db i am not finding any answers can guys help to this problem
The short answer is: it is not recommended to access SonarQube DB to get information, so forget about directly manipulating SQ's database.
A longer answer might be: have a look at SonarQube's webservice API, especially these ones :
http://nemo.sonarqube.org/api_documentation/api/tests/list
http://nemo.sonarqube.org/api_documentation/api/tests/covered_files
The first one should allow you to retrieve all test id then you can pass the ID you're looking for to the second webservice then check the size of the files array... but I don't think that this will be easy as it isn't straightforward to get the testFileId you need to feed the first webservice (you can't pass a file's key as far as I know.)
I need to create my own REST API.
I just saw strongloop and loopback and I thought it will be perfect for my project.
In fact, I was able to get mysql connected using strongloop. However, I had to create something called a "model" and I did it. But, it was like creating a new model from scratch and use it for persisting on the Datasource.
Instead, what I was looking for, is to get a REST API directly from my model on the DB.
I mean taking the models from each table on the DB and then set them up as web services.
Is that possible?
I am newbie on these technologies, although I think it is an interesting question.
Thanks
I'm not sure of a Node tool to do what you're asking, but in other languages / databases you have some choices!
The only one I'm really familiar with is postgrest.
postgrest: You import your data into a Postgres database (similar to MySQL), and it generates a REST API on top of your tables instantly. Bam. Done. I've used this and it was amazingly awesome. You can also deploy it directly on Heroku.
StrongLoop actually has a "discovery" tool for just this purpose! Read up on that page, but here's the basic code to do it. Just drop this code in a file inside /server/boot/ (the docs are wrong on that, it must be in the directory I mention). Of course, you'll need to tailor it for your use case:
var loopback = require('loopback');
var ds = loopback.createDataSource('mysql', {
"host": "yourhost",
"port": 1234,
"database": "foobar",
"username": "someuser",
"password": "somepass"
});
// Discover and build models from a given table
ds.discoverAndBuildModels('PERSON', {visited: {}, associations: true},
function (err, models) {
// Now we have a list of models keyed by the model name
// You only need the rest of this if wanted to inspect what came in...
// For example, you could find the first record from the table
// and verify info or something.
models.Person.findOne({}, function (err, person) {
if(err) {
// handle this if need be...
console.error(err);
return;
}
// Some code using `person`
});
});
Good luck!
I was supposing "discovery tool" was to find out pattern, cluster or whatever else thing into the data. But following
the recomendation of #jakarella I went with more depth.
It was even easier than that, because you can do everything via StrongLoop Arc (GUI). I always prefer cli
but to have a general look of it, sometimes is better to start with the GUI if you don't have too much idea about the subject.
Anyway,
first of all you would need to connect your datasource before (installing previously the driver).
After that, through StrongLoop Arc you can do "discover the models" choosing your tables (taking care of run Arc and restarting every time
you get a new model) and that's it, you get an API over your Datasource
(for testing go to the explorer).
I described before generally the main tasks but if anyone needs more detail pls let me know. Hope this helps to anyone else who is looking to do
something similar
thanks guys for the interest.
I'm looking for a way to create a simple HTML table that can be updated in real-time upon a database change event; specifically a new record added.
In other words, think of it like an executive dashboard. If a sale is made and a new line is added in a database (MySQL in my case) then the web page should "refresh" the table with the new line.
I have seen some information on the new using EVENT GATEWAY but all of the examples use Coldfusion as the "pusher" and not the "consumer". I would like to have Coldfusion both update / push an event to the gateway and also consume the response.
If this can be done using a combination of AJAX and CF please let me know!
I'm really just looking to understand where to get started with real-time updating.
Thank you in advance!!
EDIT / Explanation of selected answer:
I ended up going with #bpeterson76's answer because at the moment it was easiest to implement on a small scale. I really like his Datatables suggestion, and that's what I am using to update in close to real time.
As my site gets larger though (hopefully), I'm not sure if this will be a scalable solution as every user will be hitting a "listener" page and then subsequently querying my DB. My query is relatively simple, but I'm still worried about performance in the future.
In my opinion though, as HTML5 starts to become the web standard, the Web Sockets method suggested by #iKnowKungFoo is most likely the best approach. Comet with long polling is also a great idea, but it's a little cumbersome to implement / also seems to have some scaling issues.
So, let's hope web users start to adopt more modern browsers that support HTML5, because Web Sockets is a relatively easy and scalable way to get close to real time.
If you feel that I made the wrong decision please leave a comment.
Finally, here is some source code for it all:
Javascript:
note, this is a very simple implementation. It's only looking to see if the number of records in the current datatable has changed and if so update the table and throw an alert. The production code is much longer and more involved. This is just showing a simple way of getting a close to real-time update.
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.1/jquery.js"></script>
<script type="text/javascript" charset="utf-8">
var originalNumberOfRecsInDatatable = 0;
var oTable;
var setChecker = setInterval(checkIfNewRecordHasBeenAdded,5000); //5 second intervals
function checkIfNewRecordHasBeenAdded() {
//json object to post to CFM page
var postData = {
numberOfRecords: originalNumberOfRecsInDatatable
};
var ajaxResponse = $.ajax({
type: "post",
url: "./tabs/checkIfNewItemIsAvailable.cfm",
contentType: "application/json",
data: JSON.stringify( postData )
})
// When the response comes back, if update is available
//then re-draw the datatable and throw an alert to the user
ajaxResponse.then(
function( apiResponse ){
var obj = jQuery.parseJSON(apiResponse);
if (obj.isUpdateAvail == "Yes")
{
oTable = $('#MY_DATATABLE_ID').dataTable();
oTable.fnDraw(false);
originalNumberOfRecsInDatatable = obj.recordcount;
alert('A new line has been added!');
}
}
);
}
</script>
Coldfusion:
<cfset requestBody = toString( getHttpRequestData().content ) />
<!--- Double-check to make sure it's a JSON value. --->
<cfif isJSON( requestBody )>
<cfset deserializedResult = deserializeJSON( requestBody )>
<cfset numberOFRecords = #deserializedResult.originalNumberOfRecsInDatatable#>
<cfquery name="qCount" datasource="#Application.DBdsn#" username="#Application.DBusername#" password="#Application.DBpw#">
SELECT COUNT(ID) as total
FROM myTable
</cfquery>
<cfif #qCount.total# neq #variables.originalNumberOfRecsInDatatable#>
{"isUpdateAvail": "Yes", "recordcount": <cfoutput>#qCount.total#</cfoutput>}
<cfelse>
{"isUpdateAvail": "No"}
</cfif>
</cfif>
This isn't too difficult. The simple way would be to add via .append:
$( '#table > tbody:last').append('<tr id="id"><td>stuff</td></tr>');
Adding elements real-time isn't entirely possible. You'd have to run an Ajax query that updates in a loop to "catch" the change. So, not totally real-time, but very, very close to it. Your user really wouldn't notice the difference, though your server's load might.
But if you're going to get more involved, I'd suggest looking at DataTables. It gives you quite a few new features, including sorting, paging, filtering, limiting, searching, and ajax loading. From there, you could either add an element via ajax and refresh the table view, or simply append on via its API. I've been using DataTables in my app for some time now and they've been consistently cited as the number 1 feature that makes the immense amount of data usable.
--Edit --
Because it isn't obvious, to update the DataTable you call set your Datatables call to a variable:
var oTable = $('#selector').dataTable();
Then run this to do the update:
oTable.fnDraw(false);
UPDATE -- 5 years later, Feb 2016:
This is much more possible today than it was in 2011. New Javascript frameworks such as Backbone.js can connect directly to the database and trigger changes on UI elements including tables on change, update, or delete of data....it's one of these framework's primary benefits. Additionally, UI's can be fed real-time updates via socket connections to a web service, which can also then be caught and acted upon. While the technique described here still works, there are far more "live" ways of doing things today.
You can use SSE (Server Sent Events) a feature in HTML5.
Server-Sent Events (SSE) is a standard describing how servers can initiate data transmission towards clients once an initial client connection has been established. They are commonly used to send message updates or continuous data streams to a browser client and designed to enhance native, cross-browser streaming through a JavaScript API called EventSource, through which a client requests a particular URL in order to receive an event stream.
heres a simple example
http://www.w3schools.com/html/html5_serversentevents.asp
In MS SQL, you can attach a trigger to a table insert/delete/update event that can fire a stored proc to invoke a web service. If the web service is CF-based, you can, in turn, invoke a messaging service using event gateways. Anything listening to the gateway can be notified to refresh its contents. That said, you'd have to see if MySQL supports triggers and accessing web services via stored procedures. You'd also have to have some sort of component in your web app that's listening to the messaging gateway. It's easy to do in Adobe Flex applications, but I'm not sure if there are comparable components accessible in JavaScript.
While this answer does not come close to directly addressing your question, perhaps it will give you some ideas as to how to solve the problem using db triggers and CF messaging gateways.
M. McConnell
With "current" technologies, I think long polling with Ajax is your only choice. However, if you can use HTML5, you should take a look at WebSockets which gives you the functionality you want.
http://net.tutsplus.com/tutorials/javascript-ajax/start-using-html5-websockets-today/
WebSockets is a technique for two-way communication over one (TCP) socket, a type of PUSH technology. At the moment, it’s still being standardized by the W3C; however, the latest versions of Chrome and Safari have support for WebSockets.
http://html5demos.com/web-socket
Check out AJAX long polling.
Place to start Comet
No, you can't have any db code execute server side code. But you could write a service to poll the db periodically to see if a new record has been added then notify the code you have that needs pseudo real-time updates.
The browser can receive real-time updates via BOSH connection to Jabber/XMPP server. All bits and pieces can be found in this book http://professionalxmpp.com/ which I highly recommend. If you can anyhow send XMPP message upon record addition in your DB, then it is relatively easy to build the dashboard you want. You need strophe.js, Jabber/XMPP server (e.g. ejabberd), http server for proxying http-bind requests. All the details can be found in the book. A must read which I strongly believe will solve your problem.
The way I would achieve the notification is after the database update has been successfully committed I would publish an event that would tell any listening systems or even web pages that the change has occurred. I've detailed one way of doing this using an e-commerce solution in a recent blog post. The blog post shows how to trigger the event in ASP.NET but the same thing can easily be done in any other language since ultimately the trigger is performed via a REST API call.
The solution in this blog post uses Pusher but there's not reason why you couldn't install your own real-time server or use a Message Queue to communication between your app and the realtime server, which would then push the notification to the web page or client application.