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Detailed tutorial on how to use Nodejs to connect to mongodb database
Detailed tutorial on how to use Nodejs to connect to mongodb database
This article mainly introduces the implementation code of using Nodejs to connect to the mongodb database. Friends who need it can refer to
A simple example of nodejs connecting to mongodb, from the mongodb official example
1. Create package.json
First, create our project directory connect-mongodb and use it as our current directory
mkdir connect-mongodb cd connect-mongodb
Enter the npm init command to create package.json
npm init
Then, install the nodejs version driver of mongodb
npm install mongodb --save
The mongodb driver package will be installed into node_modules in the current directory
2. Start the MongoDB server
Install MongoDB and start the MongoDB database service. Please refer to my previous article or the official MongoDB documentation
3. Connect to MongoDB
Create an app.js file and add the following code to connect to the database named myNewDatabase on the server address 192.168.0.243 and mongodb port 27017
var MongoClient = require('mongodb').MongoClient,
assert = require('assert');
// Connection URL
var url = 'mongodb://192.168.0.243:27017/myNewDatabase';
MongoClient.connect(url,function(err,db){
assert.equal(null,err);
console.log("Connection successfully to server");
db.close();
});Enter the following command on the command line to run app.js
node app.js
4. Insert the document
in the app Add the following code to .js and use the insertMany method to add 3 documents to the documents collection
var insertDocuments = function(db, callback){
// get ths documents collection
var collection = db.collection('documents');
// insert some documents
collection.insertMany([
{a:1},{a:2},{a:3}
],function(err,result){
assert.equal(err,null);
assert.equal(3,result.result.n);
assert.equal(3,result.ops.length);
console.log("Inserted 3 documents into the collection");
callback(result);
});
};The insert command returns an object containing the following properties:
result The document result returned by MongoDB
ops The document with the _id field added
connection used to perform the insert operation The connection
Update the following code in app.js to call the insertDocuments method
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the server
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected successfully to server");
insertDocuments(db, function() {
db.close();
});
});Use node app.js to run in the command line
5. Query all documents
Add findDocuments function
var findDocuments = function(db,callback){
// get the documents collection
var collection = db.collection('documents');
// find some documents
collection.find({}).toArray(function(err,docs){
assert.equal(err,null);
console.log("Found the following records");
console.log(docs);
callback(docs);
});
};findDocuments function Query all documents in all 'documents' collection and add this function to the callback function of MongoClient.connect
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the server
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected correctly to server");
insertDocuments(db, function() {
findDocuments(db, function() {
db.close();
});
});
});6. Use filtering Condition (query filter) Query documents
Query documents for 'a':3
var findDocuments = function(db, callback) {
// Get the documents collection
var collection = db.collection('documents');
// Find some documents
collection.find({'a': 3}).toArray(function(err, docs) {
assert.equal(err, null);
console.log("Found the following records");
console.log(docs);
callback(docs);
});
}7 . Update document
var updateDocument = function(db,callback){
// get the documents collection
var collection = db.collection('documents');
// update document where a is 2, set b equal to 1
collection.updateOne({a:2},{
$set:{b:1}
},function(err,result){
assert.equal(err,null);
assert.equal(1,result.result.n);
console.log("updated the document with the field a equal to 2");
callback(result);
});
};The updateDocument method updates the first document that meets the condition a is 2, adds a b attribute, and sets it to 1.
Add the updateDocument method to the callback of the MongoClient.connect method
MongoClient.connect(url,function(err,db){
assert.equal(null,err);
console.log("Connection successfully to server");
insertDocuments(db,function(){
updateDocument(db,function(){
db.close();
});
});
});8. Delete the document
var removeDocument = function(db,callback){
// get the documents collection
var collection = db.collection('documents');
// remove some documents
collection.deleteOne({a:3},function(err,result){
assert.equal(err,null);
assert.equal(1,result.result.n);
console.log("removed the document with the field a equal to 3");
callback(result);
});
};Add to app.js
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the server
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected successfully to server");
insertDocuments(db, function() {
updateDocument(db, function() {
removeDocument(db, function() {
db.close();
});
});
});
});9. Create index
Indexes can improve application performance. Below your code adds an index on the 'a' attribute
var indexCollection = function(db,callback){
db.collection('documents').createIndex({
a:1
},null,function(err,results){
console.log(results);
callback();
});
};Update app.js
##
MongoClient.connect(url,function(err,db){
assert.equal(null,err);
console.log("Connection successfully to server");
insertDocuments(db,function(){
indexCollection(db,function(){
db.close();
});
});
});The above is the detailed content of Detailed tutorial on how to use Nodejs to connect to mongodb database. For more information, please follow other related articles on the PHP Chinese website!
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