简介
MongoDB is a document database designed for ease of development and scaling。
mongoDB是一个文档数据库，旨在简化开发和扩展.
A record in MongoDB is a document, which is a data structure composed of field and value pairs. MongoDB documents are similar to JSON objects. The values of fields may include other documents, arrays, and arrays of documents.
类似其他关系型数据库，在mongoDB中一个记录叫做document，是由名称和值对组成的数据结构。类似json对象。
类比mysql关系数据库
类比如下图所示，document 类似 一行record，connection类似一张表table；
简单shell操作
管理员身份打开cmd，运行mongo，前提是将bin目录写入到环境变量中。
安装参考：https://www.jianshu.com/p/59079c9832e9
1.显示所有数据库和正在使用的默认数据库test
> show dbs
admin 0.000GB
config 0.000GB
local 0.000GB
> db
test
>
2.use切换数据库，没有的话新建一个数据库，新建一个collection,相当于关系数据库中的表，插入一条数据db.myCollection.insertOne(),插入多条数据db.myCollection.insert({x:2},{x:3})
> use myNewDatabase
switched to db myNewDatabase
> db.myCollection.insertOne({x: 1})
{
"acknowledged" : true,
"insertedId" : ObjectId("5cbd255be647b2c115594ba6")
}
> db.myCollection.insert({x:2},{x:3})
WriteResult({
"nInserted" : 0,
"writeError" : {
"code" : 13297,
"errmsg" : "db already exists with different case already have:
[myNewDataBase] trying to create [myNewDatabase]"
}
})
3.删除数据库db.dropDatabase()
> db.dropDatabase()
{ "dropped" : "myNewDatabase", "ok" : 1 }
> show dbs
admin 0.000GB
config 0.000GB
local 0.000GB
nodejs中操作mongodb
前提是数据库服务已经启动，管理员身份打开 cmd
net start mongodb //启动服务
net stop mongodb //停止服务
-
Init初始化文件目录
新建一个文件夹例如node-mongodb，使用npm init初始化package.json，npm install mongodb -S
mongoDB的版本是3.2版本，以下用3.2版本的写法
新建一个index.js文件
const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
//connection url
const url = 'mongodb://127.0.0.1:27017';
//database name
const dbname = 'myNewDataBase';
//create new mongodbClient
const client = new MongoClient(url,{ useNewUrlParser: true });
client.connect((err) => {
assert.equal(null,err);
console.log('Connected successfully to server');
client.close();
})
node index.js，数据库链接成功
-
操作数据库（insert，find，update，delete，indexes（索引））
//index.js
const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
//connection url
const url = 'mongodb://127.0.0.1:27017';
//database name
const dbname = 'myNewDataBase';
//create new mongodbClient
const client = new MongoClient(url,{ useNewUrlParser: true });
client.connect((err) => {
assert.equal(null,err);
console.log('Connected successfully to server');
//3.0版本新写法
const db = client.db(dbname);
insertDocuments(db,() => {
// find
// findDocuments(db,() => {
// client.close();
// })
//update
// updateDocument(db,() => {
// //remove
// removeDocument(db,() => {
// client.close();
// });
// });
indexCollection(db,() => {
client.close();
})
})
})
//insert
const insertDocuments = (db,callback) => {
//get the document collection(相当于拿到一个表，没有的话创建一个表)
const collection = db.collection('myCollection');
collection.insertOne(
{a: 4}
,(err,result) => {
assert.equal(err, null);
console.log("Inserted 3 documents into the collection");
callback(result);
})
}
//find
const findDocuments = (db,callback) => {
const collection = db.collection('myCollection');
collection.find({}).toArray((err,docs) => {
console.log('Found the following records')
console.log(docs);
callback(docs);
});
}
//update
const updateDocument = (db,callback) => {
//get the document collection
const collection = db.collection('myCollection');
//update
collection.updateOne({a: 2},{ $set: { b: 1} },(err,result) => {
assert.equal(err, null);
console.log("Updated the document with the field a equal to 2");
callback(result);
})
}
//remove
const removeDocument = (db,callback) => {
const collection = db.collection('myCollection');
collection.deleteOne({ a: 3},(err,result) => {
assert.equal(err, null);
console.log("Removed the document with the field a equal to 3");
callback(result);
})
}
//Index a Collection
const indexCollection = (db,callback) => {
db.collection('myCollection').createIndex(
{ "a": 1 },
null,
function(err, results) {
console.log(results);
callback();
}
);
}
运行node index.js，显示如下结果
E:\workCode\node-mongodb>node index.js
Connected successfully to server
E:\workCode\node-mongodb>node index.js
Connected successfully to server
Inserted 3 documents into the collection
E:\workCode\node-mongodb>node index.js
Connected successfully to server
Inserted 3 documents into the collection
Found the following records
[ { _id: 5cbd6ee9ef77ab2d6c4a89dd, a: 4 },
{ _id: 5cbd747a716b2b08e463ccee, a: 4 } ]
E:\workCode\node-mongodb>node index.js
Connected successfully to server
Inserted 3 documents into the collection
Updated the document with the field a equal to 2
E:\workCode\node-mongodb>node index.js
Connected successfully to server
Inserted 3 documents into the collection
Updated the document with the field a equal to 2
Removed the document with the field a equal to 3
E:\workCode\node-mongodb>node index.js
Connected successfully to server
Inserted 3 documents into the collection
a_
参考：
https://docs.mongodb.com/manual/mongo/#start-the-mongo-shell-and-connect-to-mongodb
http://www.mongoing.com/archives/3818
http://mongodb.github.io/node-mongodb-native/3.2/quick-start/quick-start/
