node.js学习笔记(7)--Node.js与MongoDB简单交互

1.创建工程

E:\test>express mongo -e

create : mongo
create : mongo/package.json
create : mongo/app.js
create : mongo/public
create : mongo/public/javascripts
create : mongo/views
create : mongo/views/index.ejs
create : mongo/views/error.ejs
create : mongo/routes
create : mongo/routes/index.js
create : mongo/routes/users.js
create : mongo/public/images
create : mongo/public/stylesheets
create : mongo/public/stylesheets/style.css
create : mongo/bin
create : mongo/bin/www

install dependencies:
> cd mongo && npm install

run the app:
> SET DEBUG=mongo:* & npm start

E:\test>

2.安装MongoDB模块

E:\test>cd mongo

E:\test\mongo>npm install mongodb -save
mongodb@2.1.14 node_modules\mongodb
├── es6-promise@3.0.2
├── readable-stream@1.0.31 (isarray@0.0.1, string_decoder@0.10.31, inherits@2
.0.1, core-util-is@1.0.2)
└── mongodb-core@1.3.13 (bson@0.4.22, require_optional@1.0.0)

E:\test\mongo>

npm install 与 npm install -save的区别是：后者安装的同时，将信息写入package.json中项目路径中，如果有package.json文件时，直接使用npm install方法就可以根据dependencies配置安装所有的依赖包，这样代码提交到github时，就不用提交node_modules这个文件夹了。

3.连接MongoDB数据库

修改app.js文件
我们可以删除如下代码：（当然不删没什么关系）

// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});

// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: err
});
});
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: {}
});
});

加上监听让我们能通过入口启动（也就是输入 node app 不需要输入 npm start了）

app.listen(3000, function () {
console.log('app is listening at port 3000');
});

声明MongoClient

var MongoClient = require('mongodb').MongoClient;

连接mongodb (其中localhost是地址后面跟的是端口以及数据库名字，请根据自己情况修改)

var url = 'mongodb://localhost:27017/first';
MongoClient.connect(url, function(err, db) {
console.log("数据库连接成功");
db.close();
});

启动服务（我们现在输入node app启动）

E:\test\mongo>node app
module.js:340
throw err;
^

Error: Cannot find module 'express'
at Function.Module._resolveFilename (module.js:338:15)
at Function.Module._load (module.js:289:25)
at Module.require (module.js:366:17)
at require (module.js:385:17)
at Object.<anonymous> (E:\test\mongo\app.js:1:77)
at Module._compile (module.js:435:26)
at Object.Module._extensions..js (module.js:442:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:313:12)
at Function.Module.runMain (module.js:467:10)

好吧，报错了 原来是我们忘记安装依赖模块了

E:\test\mongo>npm install
ejs@2.3.4 node_modules\ejs

debug@2.2.0 node_modules\debug
└── ms@0.7.1

serve-favicon@2.3.0 node_modules\serve-favicon
├── etag@1.7.0
├── fresh@0.3.0
├── ms@0.7.1
└── parseurl@1.3.1

cookie-parser@1.3.5 node_modules\cookie-parser
├── cookie-signature@1.0.6
└── cookie@0.1.3

morgan@1.6.1 node_modules\morgan
├── on-headers@1.0.1
├── basic-auth@1.0.3
├── depd@1.0.1
└── on-finished@2.3.0 (ee-first@1.1.1)

express@4.13.4 node_modules\express
├── escape-html@1.0.3
├── array-flatten@1.1.1
├── content-type@1.0.1
├── serve-static@1.10.2
├── etag@1.7.0
├── range-parser@1.0.3
├── parseurl@1.3.1
├── vary@1.0.1
├── utils-merge@1.0.0
├── content-disposition@0.5.1
├── merge-descriptors@1.0.1
├── path-to-regexp@0.1.7
├── methods@1.1.2
├── cookie-signature@1.0.6
├── fresh@0.3.0
├── cookie@0.1.5
├── depd@1.1.0
├── qs@4.0.0
├── finalhandler@0.4.1 (unpipe@1.0.0)
├── on-finished@2.3.0 (ee-first@1.1.1)
├── proxy-addr@1.0.10 (forwarded@0.1.0, ipaddr.js@1.0.5)
├── send@0.13.1 (destroy@1.0.4, statuses@1.2.1, ms@0.7.1, mime@1.3.4, http
rors@1.3.1)
├── accepts@1.2.13 (negotiator@0.5.3, mime-types@2.1.10)
└── type-is@1.6.12 (media-typer@0.3.0, mime-types@2.1.10)

body-parser@1.13.3 node_modules\body-parser
├── bytes@2.1.0
├── content-type@1.0.1
├── depd@1.0.1
├── qs@4.0.0
├── iconv-lite@0.4.11
├── on-finished@2.3.0 (ee-first@1.1.1)
├── http-errors@1.3.1 (statuses@1.2.1, inherits@2.0.1)
├── raw-body@2.1.6 (unpipe@1.0.0, bytes@2.3.0, iconv-lite@0.4.13)
└── type-is@1.6.12 (media-typer@0.3.0, mime-types@2.1.10)

E:\test\mongo>

再来，搞定了^-^

E:\test\mongo>node app
app is listening at port 3000
数据库连接成功

4.对数据库进行操作

插入数据到数据库：

增加下面代码

var insertDocument = function(db, callback) {
//连接表
var collection =db.collection('first');
var user={
name:'Dandy',
age:18
}
//插入数据
collection.insertOne( user, function(err, result) {
if(err){
console.log(err)
}
console.log("插入成功");
callback();
});
};

修改数据库连接代码

MongoClient.connect(url, function(err, db) {
console.log("数据库连接成功");
insertDocument(db,function(){
db.close();
})
});

插入成功

E:\test\mongo>node app
app is listening at port 3000
数据库连接成功插入成功

查询数据库中数据：

增加如下代码

var findRestaurants = function(db, callback) {
var cursor =db.collection('first').find( );
cursor.each(function(err, result) {
if (result != null) {
console.log(result);
} else {
callback();
}
});
};

修改数据库连接代码

MongoClient.connect(url, function(err, db) {
console.log("数据库连接成功");
findRestaurants(db, function() {
db.close();
});
});

查询成功（ctrl+c可以关闭node服务）

E:\test\mongo>node app
app is listening at port 3000
数据库连接成功插入成功
^C
E:\test\mongo>node app
app is listening at port 3000
数据库连接成功{ _id: 56fc8e6d58257d7101dfafa0, name: 'tom', age: 13 }
{ _id: 56fc907858257d7101dfafa2, name: 'tom2', age: 2 }
{ _id: 56fc907858257d7101dfafa3, name: 'tom3', age: 3 }
{ _id: 56fc907858257d7101dfafa4, name: 'tom4', age: 4 }
{ _id: 56fc907858257d7101dfafa5, name: 'tom5', age: 5 }
{ _id: 56fc907858257d7101dfafa6, name: 'tom6', age: 6 }
{ _id: 56fc907858257d7101dfafa7, name: 'tom7', age: 7 }
{ _id: 56fc907858257d7101dfafa8, name: 'tom8', age: 8 }
{ _id: 56fc907858257d7101dfafa9, name: 'tom9', age: 9 }
{ _id: 56fccb1c8865f98415ed939f, name: 'Dandy', age: 18 }

条件查询：
修改findRestaurants代码

var findRestaurants = function(db, callback) {
var cursor =db.collection('first').find({name:'Dandy'} );
cursor.each(function(err, result) {
if (result != null) {
console.log(result);
} else {
callback();
}
});
};

查询成功

E:\test\mongo>node app
app is listening at port 3000
数据库连接成功{ _id: 56fccb1c8865f98415ed939f, name: 'Dandy', age: 18 }

or查询：
修改findRestaurants代码

var findRestaurants = function(db, callback) {
var cursor =db.collection('first').find({$or :[{name:'Dandy'},{age:3}]});
cursor.each(function(err, result) {
if (result != null) {
console.log(result);
} else {
callback();
}
});
};

查询成功

E:\test\mongo>node app
app is listening at port 3000
数据库连接成功{ _id: 56fc907858257d7101dfafa3, name: 'tom3', age: 3 }
{ _id: 56fccb1c8865f98415ed939f, name: 'Dandy', age: 18 }

修改数据库中数据

增加如下代码

var updateRestaurants = function(db, callback) {
var collection =db.collection('first');
collection.updateOne({name:"Dandy"},{$set: {age:13}}, function(err, results) {
console.log(results.result);
callback();
});
};

修改数据库连接代码

MongoClient.connect(url, function(err, db) {
console.log("数据库连接成功");
updateRestaurants(db, function() {
findRestaurants(db,function(){
db.close();
})
});
});

修改成功

E:\test\mongo>node app
app is listening at port 3000
数据库连接成功{ ok: 1, nModified: 0, n: 1 }
{ _id: 56fc907858257d7101dfafa3, name: 'tom3', age: 3 }
{ _id: 56fccb1c8865f98415ed939f, name: 'Dandy', age: 13 }

删除数据库中数据

增加如下代码

var removeRestaurants = function(db, callback) {
var collection =db.collection('first');
collection.deleteMany(
{ name: "tom2" },
function(err, results) {
console.log(results.result);
callback();
}
);
};

修改findRestaurants代码（改为查询所有）

var findRestaurants = function(db, callback) {
var cursor =db.collection('first').find();
cursor.each(function(err, result) {
if (result != null) {
console.log(result);
} else {
callback();
}
});
};

修改数据库连接代码

MongoClient.connect(url, function(err, db) {
console.log("数据库连接成功");
removeRestaurants(db, function() {
findRestaurants(db,function(){
db.close();
})
});
});

删除成功

E:\test\mongo>node app
app is listening at port 3000
数据库连接成功{ ok: 1, n: 0 }
{ _id: 56fc8e6d58257d7101dfafa0, name: 'tom', age: 13 }
{ _id: 56fc907858257d7101dfafa3, name: 'tom3', age: 3 }
{ _id: 56fc907858257d7101dfafa4, name: 'tom4', age: 4 }
{ _id: 56fc907858257d7101dfafa5, name: 'tom5', age: 5 }
{ _id: 56fc907858257d7101dfafa6, name: 'tom6', age: 6 }
{ _id: 56fc907858257d7101dfafa7, name: 'tom7', age: 7 }
{ _id: 56fc907858257d7101dfafa8, name: 'tom8', age: 8 }
{ _id: 56fc907858257d7101dfafa9, name: 'tom9', age: 9 }
{ _id: 56fccb1c8865f98415ed939f, name: 'Dandy', age: 13 }

5.其他

本文并没有对代码进行分层结构化，但是建议最好还是分层。

学习了本节我们能够简单的对数据库进行增删改查。
如果想深入了解的请看这里：https://docs.mongodb.org/getting-started/node