用Node.js通过一个简单的示例访问MongoDB

我们修改了下一页的示例。

假设可以使用用户名scott和密码tiger123来访问MongoDB。

数据插入

#! /usr/bin/node
//
//  mongodb_insert.js
//
//                  May/03/2020
// ----------------------------------------------------------------
console.log ("*** 開始 ***")

const host = 'scott:tiger123@localhost'
const port = 27017

const MongoClient = require('mongodb').MongoClient
const assert = require('assert')

const url = 'mongodb://' + host + ':' + port

// Database Name
const dbName = 'myproject'
const client = new MongoClient(url,
    {useNewUrlParser: true,useUnifiedTopology: true})

client.connect(function(err) {
  assert.equal(null, err)
  console.log("Connected successfully to server")

  const db = client.db(dbName)

  insertDocuments(db, function() {
    client.close()
    console.log ("*** 終了 ***")
  })
})

// ----------------------------------------------------------------
const insertDocuments = function(db, callback) {
  // Get the documents collection
  const collection = db.collection('documents')
  // Insert some documents
  collection.insertMany([
    {aa : 10}, {bb : 20}, {cc : 30}, {dd : 40}
  ], function(err, result) {
    assert.equal(err, null)
    assert.equal(4, result.result.n)
    assert.equal(4, result.ops.length)
    console.log("Inserted 4 documents into the collection")
    callback(result)
  })
}
// ----------------------------------------------------------------

执行结果

$ export NODE_PATH=/usr/lib/node_modules
$ ./mongodb_insert.js
*** 開始 ***
Connected successfully to server
Inserted 4 documents into the collection
*** 終了 ***

阅读数据

#! /usr/bin/node
//
//  mongodb_read.js
//
//                  May/03/2020
// ----------------------------------------------------------------
console.log ("*** 開始 ***")

const host = 'scott:tiger123@localhost'
const port = 27017

const MongoClient = require('mongodb').MongoClient
const assert = require('assert')

const url = 'mongodb://' + host + ':' + port 

const dbName = 'myproject'
const client = new MongoClient(url,
    {useNewUrlParser: true,useUnifiedTopology: true})

client.connect(function(err) {
    assert.equal(null, err)
    console.log("Connected correctly to server")

    const db = client.db(dbName)

    findDocuments(db, function() {
        client.close()
console.log ("*** 終了 ***")
        })
})

// ----------------------------------------------------------------
const findDocuments = function(db, callback) {
  const collection = db.collection('documents')
  collection.find({}).toArray(function(err, docs) {
    assert.equal(err, null)
    console.log("Found the following records")
    console.log(docs)
    callback(docs)
  })
}
// ----------------------------------------------------------------

执行结果

$ export NODE_PATH=/usr/lib/node_modules
$ ./mongodb_read.js
*** 開始 ***
Connected correctly to server
Found the following records
[
  { _id: 5eafbfd5a6a9fb12219e7f50, aa: 10 },
  { _id: 5eafbfd5a6a9fb12219e7f51, bb: 20 },
  { _id: 5eafbfd5a6a9fb12219e7f52, cc: 30 },
  { _id: 5eafbfd5a6a9fb12219e7f53, dd: 40 }
]
*** 終了 ***