Develop Reference

couchdb views: return all fields in doc as map

I have a doc in couchDB:
{
"id":"avc",
"type":"Property",
"username":"user1",
"password":"password1",
"server":"localhost"
}
I want to write a view that returns a map of all these fields.
The map should look like this: [{"username","user1"},{"password","password1"},{"server","localhost"}]
Here's pseudocode of what I want -
HashMap<String,String> getProperties()
{
HashMap<String,String> propMap;
if (doc.type == 'Property')
{
//read all fields in doc one by one
//get value and add field/value to the map
}
return propMap;
}
I am not sure how to do the portion that I have commented above. Please help.
Note: right now, I want to add username, password and server fields and their values in the map. However, I might keep adding more later on. I want to make sure what I do is extensible.
I considered writing a separate view function for each field. Ex: emit("username",doc.username).
But this may not be the best way to do this. Also needs updates every time I add a new field.

First of all, you have to know:
In CouchDB, you'll index documents inside a view with a key-value pair. So if you index the property username and server, you'll have the following view:
[
{"key": "user1", "value": null},
{"key": "localhost", "value": null}
]
Whenever you edit a view, it invalidates the index so Couch has to rebuild the index. If you were to add new fields to that view, that's something you have to take into account.
If you want to query multiple fields in the same query, all those fields must be in the same view. If it's not a requirement, then you could easily build an index for every field you want.
If you want to index multiple fields in the same view, you could do something like this:
// We define a map function as a function which take a single parameter: The document to index.
(doc) => {
// We iterate over a list of fields to index
["username", "password", "server"].forEach((key, value) => {
// If the document has the field to index, we index it.
if (doc.hasOwnProperty(key)) {
// map(key,value) is the function you call to index your document.
// You don't need to pass a value as you'll be able to get the macthing document by using include_docs=true
map(doc[key], null);
}
});
};
Also, note that Apache Lucene allows to make full-text search and might fit better your needs.

Contentful JS: Unable to retrieve entries by matching Reference field

I am using Contentful's Javascript API to build a project. Currently, I'm having an issue where I get "undefined" as a return for the following call.
const query = {
content_type: "vehicle",
include: 2,
select: "fields",
"fields.site.fields.siteName[match]": id
};
I've set up "vehicle" as a model which uses a "site" reference with names, addresses and so forth. It seems to be possible to use [exist] on the first level, like
"fields.site[exists]": true
which works, but is unsatisfactory for what I need.
What I need are any Vehicles that belong to a named Site. Obviously, I've made sure to add the relevant content, and I can indeed see the data when omitting the "fields.site.fields..." line. For security purposes, I would very much not have vehicles for other sites showing up in the response.
Am I missing something? Upping the "include" level does not do anything either.

👋🏻
I believed you didn't see one sentence in the docs.
Second is fields.brand.sys.contentType.sys.id=sFzTZbSuM8coEwygeUYes which you use to to filter on fields of entries from content type 2PqfXUJwE8qSYKuM0U6w8M.
So basically to make your query work you have also to define the content type of the entry your search query is matching against.
I quickly prototyped your case in Node.js.
const { createClient } = require('contentful');
const client = createClient({
space: '...',
accessToken: '...'
});
client.getEntries({
content_type: 'vehicle',
select: 'fields',
// this is the line you're missing
'fields.site.sys.contentType.sys.id': 'site',
'fields.site.fields.siteName': 'vw-site'
}).then(({items}) => {
console.log(items);
}).catch(e => console.log(e));
You can find a detailed example in the docs
Hope that helps :)

Updating Query in Firestore

I am new to Firestore, need some help on firestore update.
I have following structure and wants to update "employee name" property. Not sure how to select and update.
Department:[
Name: Accounts
Employee:[
{Name :David,
Age :25},
{Name:Paul,
Age:27}
]
]
Here is what I was trying to do:
let depempCollectionRef = admin.firestore().collection('DepEmployee').doc('depempid')
depempCollectionRef.Department.Employee
.update({ name: 'Scott' },{merge:true})
.then(function() { console.log("Document successfully updated!"); })

Employee is just an embedded data structure in your Firestore document – so you can't address it through the reference directly. As far as Firestore is concerned, Employee is just an attribute on the Department document as Name is.
Before I propose a solution, let me point out two things:
If using update, you don't need {merge: true}. You use {merge: true} together with set to get an update-like behavior, if the document already exists.
I wouldn't use an Array of employees. It might make more sense to store the employees in their own collection in Firestore and then just list their reference IDs (= foreign keys) here. As a general rule of thumb: try to keep your data structure flat. Also use Arrays only, if you need to maintain a certain order of items.
A) If you have a separate collection for employees, updating the name is as easy as:
employeeCollection.doc('101').update({name: 'Scott'})
B) If you want to store employee data within your department document, I would still store them as a map with IDs (instead of an Array) and then access them with dot notation:
Department:[
Name: Accounts
Employees:{
101: {
Name :David,
Age :25
},
102: {
Name:Paul,
Age:27
}
}
]
depempCollectionRef.Department
.set({ ['101.name']: 'Scott' }, {merge:true})
C) And if you really want to store the data embedded in an Array, I believe you have to read and update the whole Array (not sure, if there is a better solution):
const employeesSnap = await depempCollectionRef.Department.get()
const updatedEmployees = changeNameOfScottInArray()
depempCollectionRef.Department
.update({ 'Employees': updatedEmployees })
I didn't test this code, but I hope you get the gist of it!
I'd recommend you flatten your data structure by creating a separate Employee collection and then just referencing them by their foreign key in your department (solution A).

Mongo check if a document already exists

In the MEAN app I'm currently building, the client-side makes a $http POST request to my API with a JSON array of soundcloud track data specific to that user. What I now want to achieve is for those tracks to be saved to my app database under a 'tracks' table. That way I'm then able to load tracks for that user from the database and also have the ability to create unique client URLs (/tracks/:track)
Some example data:
{
artist: "Nicole Moudaber"
artwork: "https://i1.sndcdn.com/artworks-000087731284-gevxfm-large.jpg?e76cf77"
source: "soundcloud"
stream: "https://api.soundcloud.com/tracks/162626499/stream.mp3?client_id=7d7e31b7e9ae5dc73586fcd143574550"
title: "In The MOOD - Episode 14"
}
This data is then passed to the API like so:
app.post('/tracks/add/new', function (req, res) {
var newTrack;
for (var i = 0; i < req.body.length; i++) {
newTrack = new tracksTable({
for_user: req.user._id,
title: req.body[i].title,
artist: req.body[i].artist,
artwork: req.body[i].artwork,
source: req.body[i].source,
stream: req.body[i].stream
});
tracksTable.find({'for_user': req.user._id, stream: req.body[i].stream}, function (err, trackTableData) {
if (err)
console.log('MongoDB Error: ' + err);
// stuck here - read below
});
}
});
The point at which I'm stuck, as marked above is this: I need to check if that track already exists in the database for that user, if it doesn't then save it. Then, once the loop has finished and all tracks have either been saved or ignored, a 200 response needs to be sent back to my client.
I've tried several methods so far and nothing seems to work, I've really hit a wall and so help/advice on this would be greatly appreciated.

Create a compound index and make it unique.
Using the index mentioned above will ensure that there are no documents which have the same for_user and stream.
trackSchema.ensureIndex( {for_user:1, stream:1}, {unique, true} )
Now use the mongoDB batch operation to insert multiple documents.
//docs is the array of tracks you are going to insert.
trackTable.collection.insert(docs, options, function(err,savedDocs){
//savedDocs is the array of docs saved.
//By checking savedDocs you can see how many tracks were actually inserted
})
Make sure to validate your objects as by using .collection we are bypassing mongoose.

Make a unique _id based on user and track. In mongo you can pass in the _id that you want to use.
Example {_id : "NicoleMoudaber InTheMOODEpisode14",
artist: "Nicole Moudaber"
artwork: "https://i1.sndcdn.com/artworks-000087731284-gevxfm-large.jpg?e76cf77"
source: "soundcloud"
stream: "https://api.soundcloud.com/tracks/162626499/stream.mp3? client_id=7d7e31b7e9ae5dc73586fcd143574550"
title: "In The MOOD - Episode 14"}
_id must be unique and won't let you insert another document with the same _id. You could also use this to find the record later db.collection.find({_id : NicoleMoudaber InTheMOODEpisode14})
or you could find all tracks for db.collection.find({_id : /^NicoleMoudaber/}) and it will still use the index.
There is another method to this that I can explain if you dont' like this one.
Both options will work in a sharded environment as well as a single replica set. "Unique" indexes do not work in a sharded environment.

Soundcloud API provides a track id, just use it.
then before inserting datas you make a
tracks.find({id_soundcloud : 25645456}).exec(function(err,track){
if(track.length){ console.log("do nothing")}else {//insert}
});

Saving node.js post data to show all records that have been added since the web application was started

I'm working on a web application using node.js that has a form containing basic information about a person. I need to have all records that have been added since the web application was started display on the submit page.
I believe that I need to create an array to store this information but this is where my confusion starts. I'm not sure where to create the array to add information to. I suspect it should be in app.js where I call app.post('/add', routes.add);
I think it should maybe something like this going from an example I found here How do I add a new complex entry to a javascript array?:
// Routes
app.get('/', routes.index);
app.post('/add', routes.add);
var people = [{name, country, date, email, phone}];
people.push({name, country, date, email phone});
However the array looks like it will only hold enough information for 1 person.
Please let me know if my question is not clear enough and I will try to clarify
Thanks in advance!
Edit: I believe that when I am calling routes.add this code is executed from my index.js file
exports.add = function(req, res){
res.render('add', { title: 'Person added',
name: req.body.name,
country: req.body.country,
date: req.body.birthday,
email: req.body.email,
phone: req.body.phone});
};
and in my add.jade file:
h1 Info Added
p Name: #{name}
p Country: #{country}
p Date: #{date}
p Email: #{email}
p Phone: #{phone}

There are a few things to maybe get you started.
Database
I suggest you move the database to another file, that way you may replace it with a 'real' database later. Ie. do something like this:
create a lib directory in app root,
create a db.js in that directory,
put this code in the db.js:
var database = [],
counter = 0;
// add method adds a new object to db.
exports.add = function(person) {
person.id = counter;
counter = counter + 1;
database.push(person);
return id; // we return id, so that we can use it as a reference to this object.
}
// get method retreives the object by id.
exports.get = function(id) {
return database[id]; // this will return undefined if there is no such id
};
exports.list = function(){
return database;
}
Now you have a database.
Controllers
You use the db in other files like this:
var people = require('lib/db');
// or if you're in a routes directory,require('../lib/db') or appropriate path
people.add({name: 'Sarah'}); // returns 0
people.add({name: 'Zlatko'}); // returns 1
people.get(1); // returns {name: 'Zlatko'}
Now in your routes/index.js you can include your database and have this to save or retreive an user or all users. Somehing similar to your exports.add:
var id = people.add({name: req.body.name, email: req.body.email});
res.render('add', people.get(id));
You can also create a 'people' view and just pass it {people: people.list()} object as parameters array.
I didn't include any validation, checking, anything ,to make the example more clear. This db can hold more then one person, and it's enough to get you started. And I think it is clear in what it does.
I hope this helps.