https://www.w3schools.com/nodejs/nodejs_mongodb.asp
dbo.collection("tours").insertOne(myobj, callback) vs
db.collection("tours").insertOne(myobj, callback) [notice: url has database name or not)
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("mydb");
var myobj = { name: "Company Inc", address: "Highway 37" };
dbo.collection("customers").insertOne(myobj, function(err, res) {
if (err) throw err;
console.log("1 document inserted");
db.close();
});
});
var MongoClient = require('mongodb').MongoClient,
assert = require('assert'),
Hapi = require('hapi');
var url = 'mongodb://localhost:27017/learning_mongo'
var server = new Hapi.Server();
server.connection({
port:8080
})
server.route( [
// Get tour list
{
method: 'GET',
path: '/api/tours',
config: {json: {space: 2}},
handler: function(request, reply) {
var findObject = {};
for (var key in request.query) {
findObject[key] = request.query[key]
}
collection.find(findObject).toArray(function(error, tours) {
assert.equal(null,error);
reply(tours);
})
}
},
// Add new tour
{
method: 'POST',
path: '/api/tours',
handler: function(request, reply) {
collection.insertOne(request.payload, function(error, result) {
assert.equal(null,error);
reply(request.payload);
})
}
},
// Get a single tour
{
method: 'GET',
path: '/api/tours/{name}',
config: {json: {space: 2}},
handler: function(request, reply) {
collection.findOne({"tourName":request.params.name}, function(error, tour) {
assert.equal(null,error);
reply(tour);
})
}
},
// Update a single tour
{
method: 'PUT',
path: '/api/tours/{name}',
handler: function(request, reply) {
if (request.query.replace == "true") {
request.payload.tourName = request.params.name;
console.log(request.payload);
collection.replaceOne({"tourName": request.params.name},
request.payload,
function(error, results) {
collection.findOne({"tourName":request.params.name},
function(error, results) {
reply(results);
})
})
} else {
collection.updateOne({tourName:request.params.name},
{$set: request.payload},
function(error, results) {
collection.findOne({"tourName":request.params.name}, function(error, results) {
reply(results);
})
})
}
}
},
// Delete a single tour
{
method: 'DELETE',
path: '/api/tours/{name}',
handler: function(request, reply) {
collection.deleteOne({tourName:request.params.name},
function(error, results) {
reply ().code(204);
})
}
},
// Home page
{
method: 'GET',
path: '/',
handler: function(request, reply) {
reply( "Hello world from Hapi/Mongo example.")
}
}
])
MongoClient.connect(url, function(err, db) {
assert.equal(null,err);
console.log("connected correctly to server");
collection = db.collection('tours');
server.start(function(err) {
console.log('Hapi is listening to http://localhost:8080')
})
})the collection in MongoClient.connect() above:
They mean different things. If you use var the variable is declared within the scope you are in (e.g. of the function). If you don't use var, the variable bubbles up through the layers of scope until it encounters a variable by the given name or the global object (window, if you are doing it in the browser), where it then attaches. It is then very similar to a global variable. However, it can still be deleted with delete (most likely by someone else's code who also failed to use var). If you use var in the global scope, the variable is truly global and cannot be deleted.
This is, in my opinion, one of the most dangerous issues with javascript, and should be deprecated, or at least raise warnings over warnings. The reason is, it's easy to forget var and have by accident a common variable name bound to the global object. This produces weird and difficult to debug behavior.
https://stackoverflow.com/questions/2485423/is-using-var-to-declare-variables-optional
findOne() vs find()
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("mydb");
dbo.collection("customers").findOne({}, function(err, result) {
if (err) throw err;
console.log(result.name);
db.close();
});
});var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("mydb");
dbo.collection("customers").find({}).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});The Result Object
As you can see from the result of the example above, the result can be converted into an array containing each document as an object.
To return e.g. the address of the third document, just refer to the third array object's address property:
Example
Return the address of the third document:
console.log(result[2].address);
Which will produce this result:
Apple st 652
Sort the result alphabetically by name:
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("mydb");
var mysort = { name: 1 };
dbo.collection("customers").find().sort(mysort).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});
Delete the document with the address "Mountain 21":
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("mydb");
var myquery = { address: 'Mountain 21' };
dbo.collection("customers").deleteOne(myquery, function(err, obj) {
if (err) throw err;
console.log("1 document deleted");
db.close();
});
});