# MongoDB
## 使用MongoDB
```
Mongo資料庫 > collection > document
SQL資料庫 > 資料表 > 資料列
```
使用MongoLab 當練習範例
!!注意，MongoLab於2016二月底改名為mLab，連結的資料庫路徑也改了
```
https://mlab.com/home
```
1.先註冊帳號
2.創建資料庫，選地區時記得選擇有免費的
3.創建database內的user
4.創建database內的collection
5.在collection內加入document
### 如何測試剛創好的資料庫?
使用Robomongo
點選Download，選最下面的免費選項下載
1.下載完後開啟，先點選左上方的create
2.設定一下相關database url、port、username、password(database的，不是你帳戶的)
3.點選左下Test，如成功即可點選save，並進行connect
可參考
## 如何用Node.js連線到mLab?
> 注意：使用mLab註冊帳號後要去新增使用者，之後連線的url中的dbuser是你之後新增的使用者名稱跟密碼，不是輸入帳號
先使用npm 安裝
```
npm install mongodb
```
```
var mongo = require('mongodb');
var Server = mongo.Server;
var Db = mongo.Db;
```
設定server及資料庫
```
var server = new Server('ds013898.mlab.com',13898, {auto_reconnect : true});
var db = new Db('forclass', server);
```
填入database中user帳號及密碼(不是MongoLab的登入帳密)
```
db.open(function(err, client) {
client.authenticate('forclass1', 'test123', function(err, success) {
if(success){
console.log("connect success")
}else{
console.log("client.authenticate error")
};
});
});
```
完成後如下，啟動server後如在terminal中出現connect success 即表示成功連線
```
var express = require('express');
////
var mongo = require('mongodb');
var Server = mongo.Server;
var Db = mongo.Db;
var server = new Server('ds013898.mlab.com',13898, {auto_reconnect : true});
var db = new Db('forclass', server);
db.open(function(err, client) {
client.authenticate('forclass1', 'test123', function(err, success) {
if(success){
console.log("connect success")
}else{
console.log("client.authenticate error")
};
});
});
////
var app = express();
app.listen(8080);
```
## 開始操作資料庫
```
Relation DataBase MongoDB
------------------------------------------------------------
資料庫(Database) DataBase
資料表(Table) Collection
資料(Record/Row) Document
欄位(Column) Field
主索引(PK) _id
function function ( )
stored procedure mapreduce
```
1.先根據官方範例在MongoLab引入一個範例collection名為apple,而裡面的document如下
```
{
"address": {
"building": "1007",
"coord": [ -73.856077, 40.848447 ],
"street": "Morris Park Ave",
"zipcode": "10462"
},
"borough": "Bronx",
"cuisine": "Bakery",
"grades": [
{ "date": { "$date": 1393804800000 }, "grade": "A", "score": 2 },
{ "date": { "$date": 1378857600000 }, "grade": "A", "score": 6 },
{ "date": { "$date": 1358985600000 }, "grade": "A", "score": 10 },
{ "date": { "$date": 1322006400000 }, "grade": "A", "score": 9 },
{ "date": { "$date": 1299715200000 }, "grade": "B", "score": 14 }
],
"name": "Morris Park Bake Shop",
"restaurant_id": "30075445"
}
```
```
{
"address": {
"building": "1007",
"coord": [ -73.856077, 40.848447 ],
"street": "Morris Park Ave",
"zipcode": "10462"
},
"borough": "test1",
"cuisine": "banana",
"grades": [
{ "date": { "$date": 1393804800000 }, "grade": "A", "score": 2 },
{ "date": { "$date": 1378857600000 }, "grade": "A", "score": 6 },
{ "date": { "$date": 1358985600000 }, "grade": "A", "score": 10 },
{ "date": { "$date": 1322006400000 }, "grade": "A", "score": 9 },
{ "date": { "$date": 1299715200000 }, "grade": "B", "score": 14 }
],
"name": "apple Shop",
"restaurant_id": "12345"
}
```
接著回到index.js將code改成如下，應可看到query 出整個collection內容
```
var express = require('express');
////
var mongo = require('mongodb');
var Server = mongo.Server;
var Db = mongo.Db;
var server = new Server('ds013898.mlab.com',13898, {auto_reconnect : true});
var db = new Db('forclass', server);
db.open(function(err, client) {
client.authenticate('forclass1', 'test123', function(err, success) {
if(success){
console.log("connect success")
var cursor = db.collection('apple').find();
cursor.each(function(err, doc) {
console.log(doc);
db.close();
});
}else{
console.log("client.authenticate error")
};
});
});
////
var app = express();
app.listen(8080);
```
2.如果在find()，裡面放入參數，會query出所有符合的document
```
var cursor = db.collection('apple').find({ "borough": "Bronx" });
```
舉例:\
假設有個inventory collection裡面有三個資料\`
```
{ _id: 5, type: "food", item: "aaa", ratings: [ 5, 8, 9 ] }
{ _id: 6, type: "food", item: "bbb", ratings: [ 5, 9 ] }
{ _id: 7, type: "food", item: "ccc", ratings: [ 9, 5, 8 ] }
```
執行 db.inventory.find( { ratings: \[ 5, 8, 9 ] } )
將返回
```
{ "_id" : 5, "type" : "food", "item" : "aaa", "ratings" : [ 5, 8, 9 ] }
```
### 移除document
```
var cursor = db.collection('apple').remove({});
```
### 新增document
```
var cursor = db.collection('apple').insert({
title: 'web課程',
description: 'test ',
by: 'eason',
url: 'hi',
tags: ['hello'],
likes: 200
});
```
### 運用operator
以下參考至
先輸入三組document
```
db.open(function(err, client) {
client.authenticate('forclass1', 'test123', function(err, success) {
if(success){
console.log("connect success")
db.collection('apple').insert({
title: 'web課程',
description: 'test ',
by: 'eason',
url: 'hi',
tags: ['hello'],
likes: 50
});
db.collection('apple').insert({
title: 'web課程',
description: 'test ',
by: 'eason',
url: ['hi'],
tags: 'hello',
likes: 100
});
db.collection('apple').insert({
title: 'web課程',
description: 'test ',
by: 'eason',
url: true,
tags: ['hello'],
likes: 200
});
}else{
console.log("client.authenticate error")
};
});
});
```
接著改成查詢的code如下
```
db.open(function(err, client) {
client.authenticate('forclass1', 'test123', function(err, success) {
if(success){
console.log("connect success")
var cursor = db.collection('apple').find({likes : {$gt : 100}});
cursor.each(function(err, doc) {
console.log(doc);
db.close();
});
}else{
console.log("client.authenticate error")
};
});
});
```
## $gt代表大於
## $lt代表小於
## $gte大於等於
## $lte小於等於
### 使用type操作
```
db.open(function(err, client) {
client.authenticate('forclass1', 'test123', function(err, success) {
if(success){
console.log("connect success")
var cursor = db.collection('apple').find({url : {$type : 8}});
cursor.each(function(err, doc) {
console.log(doc);
db.close();
});
}else{
console.log("client.authenticate error")
};
});
});
```
type的值，數字對照表
```
Double 1
String 2
Object 3
Array 4
Binary data 5
Object id 7
Boolean 8
Date 9
Null 10
Regular Expression 11
JavaScript 13
Symbol 14
JavaScript (with scope) 15
32-bit integer 16
Timestamp 17
64-bit integer 18
```
## 使用limit()
如果為參數1代表讀到一個document，如果為五代表讀前五個document
```
var cursor = db.collection('apple').find().limit(1);
```
## 使用skip()
與limit相反，跳過skip參數個document，都是從前面往後數
```
var cursor = db.collection('apple').find().skip(2);
```
## 使用sort()
根據name的值去排列，而不是根據document的index順序
```
var cursor = db.collection('apple').find().sort({"likes":-1})
```
## 比較這兩個Find()
```
var cursor = db.collection('apple').find({},{likes:1, _id: 0});
var cursor = db.collection('apple').find({likes : {$gt : 100}},{likes:1, _id: 0});
```
發現find()的第一個參數代表:我們要從哪個地方去找東西
第二個參數代表:從那個地方要找那些東西出來
第二個參數中物件的值只有0和1，指定其他數和指定1的效果相同，0為不顯示
參考至:
中文:
英文:官方doc:
英文:官方github.io:
### 如果是下載到local端啟用
```
1.先到你的Mongo資料庫下bin的外面創建資料夾
2.cd到bin裡面把路徑複製
3.使用admin開起cmd在cd到剛複製的路徑
4.執行mongod --dbpath ../資料夾名稱/
5.即可使用robomongo連線
```
1.建造database
```
use 資料庫名稱 //如不存在即會創建新的
```
ps:用Robomongo執行以上指令如發現沒出現，需要點選新連線，才會出現
2.建造collection
```
db.createCollection("apple")
```
## Node.js 連接
```
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");
db.close();
});
```
## Mongo有新增的連接方法，參考下面文章
主要是寫關於require('mongodb').Db和require('mongodb').MongoClient的區別\
(其告知MongoClient為較新的方法，推薦使用)
## 使用Mongoose
> mongoose query 的物件沒辦法直接修改，要用 lean() 後才可修改，且 lean 可增加許多 query 效能
> 如出現連線字串後加入/\ 出現 auth error 請參考以下模板連線方式：
>
>
介紹
```
Schema ： 描述數據結構
Model ： 由Schema生成的模型
Entity ： 由Model創建的實體
```
開始使用
1\.
```
var mongoose = require('mongoose');
mongoose.connect('mongodb://user:pass@host:port/dbs');
```
(可點選mLab的tools標籤，看相關連線資料)\
如何抓取連線時的錯誤
```
mongoose.connect('mongodb://forclass1:test123@ds013898.mlab.com:13898/forclass',function(err){
if(err){throw err};
});
```
如何抓取正確連線到資料庫的訊息
```
db.once('open', function() {
console.log("connect mongo")
});
```
如何抓取連線後執行時的錯誤
```
db.on('error', console.error.bind(console, 'connection error:'));
```
完整
```
var mongoose = require("mongoose");
mongoose.connect('mongodb://forclass1:test123@ds013898.mlab.com:13898/forclass',function(err){
if(err){throw err};
});
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
console.log("connect mongo")
});
```
(存入資料時如collection名稱不存在則會自動建立)
2\.
定義model(這裡省略先定義schema，直接定義在MODEL內)
第一個參數為collection的名稱
```
var Cat = mongoose.model('Cat', {
name: String,
friends: [String],
age: Number,
});
```
3.存入資料(產生實體)
```
var kitty = new Cat({ name: 'Zildjian', friends: ['tom', 'jerry']});
kitty.age = 3;
```
4.使用save才真的存入
```
kitty.save(function (err) {
if (err) // ...
console.log('meow');
});
```
ps:如果存入資料的欄位不在schema內則不會存入
ps:如省略某些欄位沒寫，則不會顯示，亦可正常存入
```
var mongoose = require('mongoose');
mongoose.connect('mongodb://forclass1:test123@ds013898.mlab.com:13898/forclass');
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
console.log("connect");
});
var Cat = mongoose.model('Cat', {
name: String,
friends: [String],
age: Number,
});
var kitty = new Cat({ name: 'Zildjian', friends: ['tom', 'jerry']});
kitty.age = 3;
//使用save方法後才會存入
kitty.save(function (err) {
if (err) // ...
console.log('meow');
});
```
## 使用Promise
```
var User = mongoose.model('ac', new mongoose.Schema({
name:{type: String, unique: true},
password:String
}));
var list = new User({name:"s", password:"123456"});
list.save()
.then(a => console.log(a))
.catch(err => console.log(err));
```
### 注意：記得res.end回傳資料要先`JSON.stringify`
## 查詢資料
```
var Cat = mongoose.model('Cat', {
name: String,
friends: [String],
age: Number,
});
Cat.find({},function(err,doc){
console.log(doc);
});
```
得知必須使用先前定義好Model才能查找
但如果改成下面呢?
```
var Cat = mongoose.model('Cat', {});
Cat.find({},function(err,doc){
console.log(doc);
});
```
發現一樣可查找，而上面的例子我們將Schema留空，於是我們知道，可以只提供collection的參數即可，後面Schema參數如果不寫會報錯，但其可接受空的物件當參數。
#### 其他查找方法和原生相似
```
Cat.find({},{_id:1},function(err,doc){
console.log(doc);
});
```
find()
1.第一個參數為要搜尋哪些document
2.第二個參數為要顯示document內的那些資料(1代表要，0代表不要)
3.第三個參數為一個function(err,doc)\
，讀取到的資料會顯示在doc這
```
var find = Cat.find({},{time:1,_id:0},function(err,doc){
res.render("home",{text:doc});
});
```
### 我們也可先定義Schema在把他compile到model內
```
var kittySchema = mongoose.Schema({
name: String
});
var Kitten = mongoose.model('cats', kittySchema);
```
這樣和上面直接將schema在model內定義是相同的，不同之處在於有了例外定義的Schema，我們可以幫Schema指定方法
但記得使用methods函式指定方法的話，要放在model實例化之前
```
kittySchema.methods.speak = function () {
var greeting = this.name
? "Meow name is " + this.name
: "I don't have a name";
console.log(greeting);
}
```
完整版
```
var mongoose = require('mongoose');
mongoose.connect('mongodb://forclass1:test123@ds013898.mlab.com:13898/forclass');
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
console.log("connect");
});
var kittySchema = mongoose.Schema({
name: String
});
kittySchema.methods.speak = function () {
var greeting = this.name
? "Meow name is " + this.name
: "I don't have a name";
console.log(greeting);
}
//////////method要定義在model實例化之前
var Kitten = mongoose.model('cats', kittySchema);
var fluffy = new Kitten({ name: 'fluffy' });
fluffy.speak(); // "Meow name is fluffy"
```
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