NodeJS+Express+MongoDB
<div style="font-size: 20px; font-family: microsoft yahei"><h1>一、MongoDB</h1>
<p>MongoDB是开源,高性能的NoSQL数据库;支持索引、集群、复制和故障转移、各种语言的驱动程序丰富;高伸缩性;<br>MongoDB 是一个基于分布式文件存储的数据库。由 C++ 语言编写。旨在为 WEB 应用提供可扩展的高性能数据存储解决方案。<br>MongoDB 是一个介于关系数据库和非关系数据库之间的产品,是非关系数据库当中功能最丰富,最像关系数据库的。</p>
<p>官网地址:http://www.mongodb.org/</p>
<p>github:https://github.com/mongodb/</p>
<p>API Docs:http://docs.mongodb.org/manual/</p>
<p>nodejs驱动:https://github.com/mongodb/node-mongodb-native</p>
<h2>1.1、安装MongoDB</h2>
<p>下载地址:http://www.mongodb.org/downloads</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223110208261-483504933.png" alt=""></p>
<p>下载成功后点击msi文件直接安装,这里以win7_64位的操作系统为例。</p>
<h3>1.1.1、配置运行环境</h3>
<p><strong>1)、创建存放数据的文件夹</strong></p>
<p>在任意没有中文的目录下新建文件夹,如c:\data,在文件夹下存放MongoDB数据库文件与日志文件,如:</p>
<p>c:\data\db用于存放mongodb的数据文件</p>
<p>c:\data\log用于存放mongodb的日志文件</p>
<p><strong>2)、创建配置文件</strong></p>
<p>打开MongoDB的安装目录如“C:\Program Files\MongoDB\Server\3.4\bin”,并在此目录下新建一个mongo.config文件,文件内容如下:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 0, 0, 1)">##数据库目录##
dbpath</span>=<span style="color: rgba(0, 0, 0, 1)">C:\data\db
##日志输出文件##
logpath</span>=C:\data\log\db.log</pre>
</div>
<p><strong>3) 、安装Windows服务</strong></p>
<p>使用cmd进入命令行</p>
<p>使用cd切换目录到安装目录下,如:cd C:\Program Files\MongoDB\Server\3.4\bin</p>
<p>安装MongoDB服务且指定配置文件,如:</p>
<p>mongod --config "C:\Program Files\MongoDB\Server\3.4\bin\mongo.config" --install</p>
<p><strong>4)、错误处理</strong></p>
<p>如果运行过程中提示“<span style="color: rgba(255, 0, 0, 1)">无法定位程序输入点ucrtbase.terminate于动态链接库api-ms-win-crt-runtime-|1-1-0.dll</span>”错误,请下载安装“vc_redist.x64”,如果vc redis.x64安装失败请先下载补丁(KB2999226)再安装。</p>
<p>5)、<strong>添加环境变量</strong><br>在计算机->右键->高级->在环境变量PATH中加入"C:\Program Files\MongoDB\Server\3.4\bin"路径。</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223135913729-1912072794.png" alt=""></p>
<p><strong>6)、启动服务</strong><br>在cmd窗口中运行如下命令开始服务,也可以在可以在“控制面板\所有控制面板项\管理工具\服务”手动开启,注意默认是开机就自动启动服务的,可以设置成手动启动。</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223140313932-1919444716.png" alt=""></p>
<p>net start mongodb</p>
<p>停止服务</p>
<p>net stop mongodb</p>
<p>在cmd中运行如下命令</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223140514901-1813768129.png" alt=""></p>
<p>这样安装就成功了!</p>
<h3>1.1.2、运行MongoDB</h3>
<p><strong>1)、直接运行</strong></p>
<p>如果安装完成后不想做任何配置,可以直接运行,其中mongod.exe是服务,应该先启动,如:</p>
<p><strong><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223142606386-13917145.png" alt=""></strong></p>
<p>启动客户端mongo.exe文件,如:</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223142658339-392177038.png" alt=""></p>
<p><strong>2)、启动服务后运行</strong></p>
<p>使用net start mongodb或手动启动服务器运行客户端mongo.exe文件。</p>
<p><strong>3)、可视化工具</strong></p>
<p>当服务启动成功后,如果认为命令行操作不方便,可以使用robomongo等GUI工具。</p>
<p>官网:https://robomongo.org/</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223143034901-1710922317.png" alt=""></p>
<p> 第二项是一个绿色版的,解压后在文件夹中找到exe文件直接运行即可。</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223144729307-73341438.png" alt=""></p>
<h2>1.2、数据库操作</h2>
<h3>1.2.1、创建数据库与查看数据库</h3>
<p>以下实例我们创建了数据库gomall<br>> use gomall<br>switched to db gomall<br>> db<br>gomall</p>
<p>如果使用GUI工具在连接名称上右键create database也可以创建数据库:</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223145117698-2022423470.png" alt=""></p>
<p> 创建成功后如下所示:</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223145151542-639264237.png" alt=""></p>
<p>Collections表示集合,类似关系数据库中的表。</p>
<p>Functions表示函数,类似关系数据库中的存储过程与函数。</p>
<p>Users表示用户。</p>
<p>document表示记录,类似关系数据为中的记录或行。</p>
<p>如果你想查看所有数据库,可以使用 show dbs 命令:<br>> show dbs</p>
<p>MongoDB 中默认的数据库为 test,如果你没有创建新的数据库,集合将存放在 test 数据库中。</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223145435276-514677717.png" alt=""></p>
<h3>1.2.2、删除数据库</h3>
<p>> use gomall<br>switched to db gomall<br>> db.dropDatabase()<br>{ "dropped" : "gomall", "ok" : 1 }</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223145642948-166498178.png" alt=""></p>
<h3>1.2.3、插入数据</h3>
<p><strong>a)、db.集合.insert(数据)</strong></p>
<p>这里的数据可以是JSON</p>
<p>先打开shell脚本编写的界面,操作如下:</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223150045354-949588163.png" alt=""></p>
<p>db.products.insert({name:"iphone",price:1988});</p>
<p>从上图操作可以看出,没有去创建“products”集合,其实通过插入操作也会自动创建<br>_id,是mongodb自已生成的,每行数据都会存在,默认是ObjectId,可以在插入数据时插入这个键的值(支持mongodb支持的所有数据类型) </p>
<p>查看数据:db.getCollection('products').find({})</p>
<p>b)、db.表名.save(数据);</p>
<p>db.products.save({_id:2,name:"HuWei P9",price:2988});</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223150550526-1531740314.png" alt=""></p>
<p>_id可以自已插入、一个表中不一定要字段都相同,虽然insert和save方法都可以插入数据,当默认的“_id”值已存在时,调用insert方法插入会报错;而save方法不会,会更新相同的_id所在行数据的信息。</p>
<p><strong>c)、批量添加</strong></p>
<p>mongodb的shell中可以使用javascript脚本,如</p>
<p>for(var i=0;i<5;i++)db.users.save({'_id':i,'name':'zhangguo'+i,'age':i+8});</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223151830386-1273875312.png" alt=""></p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223151857448-1370277862.png" alt=""></p>
<h3>1.2.4、查询数据</h3>
<p>a)、查询集合中所有数据:db.集合.find();</p>
<p>db.users.find({name:'zhangguo0'});</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223152030136-1171741082.png" alt=""></p>
<p>b)、按条件查询(支持多条件):db.集合.find(条件); </p>
<p>db.users.find({name:'zhangguo0',age:9}); </p>
<p>对象中的条件要求同时成立</p>
<p>c)、查询第一条(支持条件):db.集合.findOne(条件);</p>
<p>d)、限制数量:db.集合.find().limit(数量);</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223152329901-1198045809.png" alt=""></p>
<p>e)、跳过指定数量:db.表名.find().skip(数量);</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223152446667-1090916017.png" alt=""></p>
<p>f)、比较查询<br>大于:$gt<br>小于:$lt<br>大于等于:$gte<br>小于等于:$lte<br>非等于:$ne</p>
<p>db.users.find({age:{'$gt':9}});</p>
<p>查找年龄大于9且小于11岁的</p>
<p>db.users.find({age:{'$gt':9,'$lt':11}});</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223152615714-1414577647.png" alt=""></p>
<p>g)、查询数量:db.表名.find().count();</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223152731682-1794920637.png" alt=""></p>
<p>h)、排序:db.表名.find().sort({"字段名":1});</p>
<p>1:表示升序,-1:表示降序</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223152910182-945066625.png" alt=""></p>
<p>i)、指定字段返回: db.表名.find({},{"字段名":0}); 参数1:返回 0:不返回</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223153115104-557227517.png" alt=""></p>
<h3>1.2.5、修改</h3>
<p>前面save在_id字段已存在是就是修改操作,按指定条件修改语法如下:</p>
<p>db.集合.update({"条件字段名":"字段值"},{$set:{"要修改的字段名":"修改后的字段值"}});</p>
<p>db.users.update({age:{'$eq':9}},{$set:{age:100}});</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223154339854-1760583125.png" alt=""></p>
<p>修改多条:</p>
<p>db.users.updateMany({age:{"$gte":10}},{$set:{age:30}});</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223161611167-855333102.png" alt=""></p>
<h3>1.2.6、删除</h3>
<p>db.集合.remove(条件);</p>
<p>db.users.remove({age:{'$gte':10}}); 删除年龄>=10岁的数据</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223154540198-1833888613.png" alt=""></p>
<h1>二、NodeJS访问MongoDB</h1>
<p>MongoDB对许多平台都提供驱动可以访问数据库,如C#、Java、Node.js等。这里以Node.js为例。</p>
<h2>2.1、安装MongoDB访问驱动</h2>
<p>使用包管理器,在命令行执行如下指令:</p>
<p>全局安装驱动</p>
<p>npm install mongodb -g</p>
<p>在当前项目中引入mongodb</p>
<p>npm install mongodb --save</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223155230807-1724719163.png" alt=""></p>
<p>这样添加驱动就成功了。</p>
<h2>2.2、添加数据</h2>
<p>在项目的根目录下新建一个db.js文件,使用Node.js操作MongoDB。</p>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223155442214-697244536.png" alt=""></p>
<p>示例代码:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">引入mongodb模块,获得客户端对象</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> MongoClient = require('mongodb'<span style="color: rgba(0, 0, 0, 1)">).MongoClient;
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">连接字符串</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> DB_CONN_STR = 'mongodb://localhost:27017/gomall'<span style="color: rgba(0, 0, 0, 1)">;
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">定义函数表达式,用于操作数据库并返回结果</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> insertData = <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(db, callback) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得指定的集合 </span>
<span style="color: rgba(0, 0, 255, 1)">var</span> collection = db.collection('users'<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">插入数据</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> data = [{_id:7,"name":'rose',"age":21},{_id:8,"name":'mark',"age":22<span style="color: rgba(0, 0, 0, 1)">}];
collection.insert(data, </span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(err, result) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">如果存在错误</span>
<span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)">(err)
{
console.log(</span>'Error:'+<span style="color: rgba(0, 0, 0, 1)"> err);
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)">;
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">调用传入的回调方法,将操作结果返回</span>
<span style="color: rgba(0, 0, 0, 1)"> callback(result);
});
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">使用客户端连接数据,并指定完成时的回调方法</span>
MongoClient.connect(DB_CONN_STR, <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(err, db) {
console.log(</span>"连接成功!"<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行插入数据操作,调用自定义方法</span>
insertData(db, <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(result) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">显示结果</span>
<span style="color: rgba(0, 0, 0, 1)"> console.log(result);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭数据库</span>
<span style="color: rgba(0, 0, 0, 1)"> db.close();
});
});</span></pre>
</div>
<p>运行结果:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 0, 0, 1)">连接成功!
{ result: { ok: </span>1, n: 2<span style="color: rgba(0, 0, 0, 1)"> },
ops:
[ { _id: </span>7, name: 'rose', age: 21<span style="color: rgba(0, 0, 0, 1)"> },
{ _id: </span>8, name: 'mark', age: 22<span style="color: rgba(0, 0, 0, 1)"> } ],
insertedCount: </span>2<span style="color: rgba(0, 0, 0, 1)">,
insertedIds: [ </span>7, 8 ] }</pre>
</div>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223160310245-1060454300.png" alt=""></p>
<h2>2.3、修改数据</h2>
<p>示例代码:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">引入mongodb模块,获得客户端对象</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> MongoClient = require('mongodb'<span style="color: rgba(0, 0, 0, 1)">).MongoClient;
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">连接字符串</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> DB_CONN_STR = 'mongodb://localhost:27017/gomall'<span style="color: rgba(0, 0, 0, 1)">;
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">定义函数表达式,用于操作数据库并返回结果</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> updateData = <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(db, callback) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得指定的集合 </span>
<span style="color: rgba(0, 0, 255, 1)">var</span> collection = db.collection('users'<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">要修改数据的条件,>=10岁的用户</span>
<span style="color: rgba(0, 0, 255, 1)">var</span>where={age:{"$gte":10<span style="color: rgba(0, 0, 0, 1)">}};
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">要修改的结果</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> set={$set:{age:95<span style="color: rgba(0, 0, 0, 1)">}};
collection.updateMany(where,set, </span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(err, result) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">如果存在错误</span>
<span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)">(err)
{
console.log(</span>'Error:'+<span style="color: rgba(0, 0, 0, 1)"> err);
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)">;
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">调用传入的回调方法,将操作结果返回</span>
<span style="color: rgba(0, 0, 0, 1)"> callback(result);
});
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">使用客户端连接数据,并指定完成时的回调方法</span>
MongoClient.connect(DB_CONN_STR, <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(err, db) {
console.log(</span>"连接成功!"<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行插入数据操作,调用自定义方法</span>
updateData(db, <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(result) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">显示结果</span>
<span style="color: rgba(0, 0, 0, 1)"> console.log(result);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭数据库</span>
<span style="color: rgba(0, 0, 0, 1)"> db.close();
});
});</span></pre>
</div>
<p>运行结果:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 0, 0, 1)">连接成功!
{ result: { n: </span>5, nModified: 5, ok: 1 }</pre>
</div>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223161804089-880485615.png" alt=""></p>
<h2>2.4、查询数据</h2>
<p>示例代码:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">引入mongodb模块,获得客户端对象</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> MongoClient = require('mongodb'<span style="color: rgba(0, 0, 0, 1)">).MongoClient;
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">连接字符串</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> DB_CONN_STR = 'mongodb://localhost:27017/gomall'<span style="color: rgba(0, 0, 0, 1)">;
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">定义函数表达式,用于操作数据库并返回结果</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> findData = <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(db, callback) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得指定的集合 </span>
<span style="color: rgba(0, 0, 255, 1)">var</span> collection = db.collection('users'<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">要查询数据的条件,<=10岁的用户</span>
<span style="color: rgba(0, 0, 255, 1)">var</span>where={age:{"$lte":10<span style="color: rgba(0, 0, 0, 1)">}};
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">要显示的字段</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> set={name:1,age:1<span style="color: rgba(0, 0, 0, 1)">};
collection.find(where,set).toArray(</span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(err, result) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">如果存在错误</span>
<span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)">(err)
{
console.log(</span>'Error:'+<span style="color: rgba(0, 0, 0, 1)"> err);
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)">;
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">调用传入的回调方法,将操作结果返回</span>
<span style="color: rgba(0, 0, 0, 1)"> callback(result);
});
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">使用客户端连接数据,并指定完成时的回调方法</span>
MongoClient.connect(DB_CONN_STR, <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(err, db) {
console.log(</span>"连接成功!"<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行插入数据操作,调用自定义方法</span>
findData(db, <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(result) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">显示结果</span>
<span style="color: rgba(0, 0, 0, 1)"> console.log(result);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭数据库</span>
<span style="color: rgba(0, 0, 0, 1)"> db.close();
});
});</span></pre>
</div>
<p>运行结果:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 0, 0, 1)">连接成功!
[ { _id: </span>0, name: 'zhangguo0', age: 8<span style="color: rgba(0, 0, 0, 1)"> },
{ _id: </span>1, name: 'zhangguo1', age: 9 } ]</pre>
</div>
<h2>2.5、删除数据</h2>
<p> 示例代码:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">引入mongodb模块,获得客户端对象</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> MongoClient = require('mongodb'<span style="color: rgba(0, 0, 0, 1)">).MongoClient;
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">连接字符串</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> DB_CONN_STR = 'mongodb://localhost:27017/gomall'<span style="color: rgba(0, 0, 0, 1)">;
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">定义函数表达式,用于操作数据库并返回结果</span>
<span style="color: rgba(0, 0, 255, 1)">var</span> findData = <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(db, callback) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得指定的集合 </span>
<span style="color: rgba(0, 0, 255, 1)">var</span> collection = db.collection('users'<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">要删除数据的条件,_id>2的用户删除</span>
<span style="color: rgba(0, 0, 255, 1)">var</span>where={_id:{"$gt":2<span style="color: rgba(0, 0, 0, 1)">}};
collection.remove(where,</span><span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(err, result) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">如果存在错误</span>
<span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)">(err)
{
console.log(</span>'Error:'+<span style="color: rgba(0, 0, 0, 1)"> err);
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)">;
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">调用传入的回调方法,将操作结果返回</span>
<span style="color: rgba(0, 0, 0, 1)"> callback(result);
});
}
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">使用客户端连接数据,并指定完成时的回调方法</span>
MongoClient.connect(DB_CONN_STR, <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(err, db) {
console.log(</span>"连接成功!"<span style="color: rgba(0, 0, 0, 1)">);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行插入数据操作,调用自定义方法</span>
findData(db, <span style="color: rgba(0, 0, 255, 1)">function</span><span style="color: rgba(0, 0, 0, 1)">(result) {
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">显示结果</span>
<span style="color: rgba(0, 0, 0, 1)"> console.log(result);
</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭数据库</span>
<span style="color: rgba(0, 0, 0, 1)"> db.close();
});
});</span></pre>
</div>
<p>运行结果:</p>
<div class="cnblogs_code">
<pre><span style="color: rgba(0, 0, 0, 1)">连接成功!
{ result: { n: </span>4, ok: 1 },</pre>
</div>
<p><img src="https://images2015.cnblogs.com/blog/63651/201612/63651-20161223162752386-496704449.png" alt=""></p>
<h1>三、NodeJS+Express+MongoDB示例</h1>
<h1>四、示例下载</h1>
<p> git:https://coding.net/u/zhangguo5/p/NodeJS002/git</p>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
</div><br><br>
来源:https://www.cnblogs.com/best/p/6212807.html
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