MongoDB权威指南(1)- 入门

jopen 9年前
     <div id="article_content" class="article_content">     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">安装</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> 解压缩出来就OK了,mongoDB缺省使用磁盘根目录的data文件夹和data\db文件夹,</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> 这两个文件夹需要手工建立,如果想使用其他路径,那么启动mongoDB的时候需要指明路径</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">运行</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> 运行CMD打开控制台窗口,导航至mongodb的bin目录,运行mongod.exe,服务器就启动起来了,按ctrl-c结束程序。</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> 另开一个控制台窗口,导航至mongodb的bin目录,运行mongo.exe来启动shell,就链接到服务器了,缺省连接到test数据库。</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">-------------------------------------------------------------------------------------------------------------</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">OK,第一章讲mongoDB如何如何牛b的我们就隔过去啦,这里直接是第二章。</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"><strong>1.一些基本概念</strong></p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> document :mongoDB里边数据的基本单位,相当于关系数据库里的行</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> collection: 相当于关系数据库的表,不过是没有数据结构定义的</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> 每个mongoDB的实例可以运行多个database,每个database有自己的collection和权限控制</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> mongoDB拥有一个强大的javascript shell,用于管理数据库和操作数据</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"> 每个document都有一个特殊的key:"_id",这个值在collection内是唯一的</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">document</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">document是一组有序的key/value对,使用json风格的数据。</p>     <div style="line-height:20px;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;" class="cnblogs_Highlighter">      <div style="position:relative !important;text-align:left !important;padding-bottom:1px 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!important;bottom:auto !important;padding-right:0px !important;border-collapse:collapse !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="ke-zeroborder">          <tbody style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;">           <tr style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;">            <td style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0.5em !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;font-size:1em !important;vertical-align:top !important;border-left-style:none !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="content"><code style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="plain">{</code><code style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;color:blue !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="string">"foo"</code> <code style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="plain">: 3, </code><code style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;color:blue !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="string">"greeting"</code> <code style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="plain">: </code><code style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;color:blue !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="string">"Hello, world!"</code><code style="position:static !important;padding-bottom:0px !important;border-right-width:0px !important;margin:0px;padding-left:0px !important;outline-width:0px !important;width:auto !important;bottom:auto !important;padding-right:0px !important;font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace !important;float:none !important;border-top-width:0px !important;border-bottom-width:0px !important;height:auto !important;font-size:1em !important;vertical-align:baseline !important;border-left-width:0px !important;top:auto !important;right:auto !important;padding-top:0px !important;left:auto !important;" class="plain">}</code></td>           </tr>          </tbody>         </table>        </div>       </div>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">key是个UTF-8字符串,value 可以是很多类型,甚至是一个嵌入的document。</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">collection</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">collection是一组document,它是无结构定义的,所以你可以把任何document存入一个collection里。</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">subcollection</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">一个习惯性的组织collection的方式,使用.号分隔,像命名空间。例如,程序里使用了一个blog,它可能包含一个collection叫 blog.post和另外一个collection叫blog.authors,这仅仅是出于组织内容的目的,它们俩看起来像是blog的子集,实际上他们没有任何关系,甚至blog也许就是不存在的。</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">database</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">一个mongoDB的实例可以运行多个database,database之间是完全独立的,每个database有自己的权限,每个database存储于磁盘的不同文件。</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"><strong>2. mongoDB shell</strong></p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">shell本身就是一个javascript解释器,让我们来干点啥来看看</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">可以进行数学运算</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> x </span>       <span style="line-height:1.5;">=</span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;">200</span>       <span style="line-height:1.5;"><br /> </span>       <span style="line-height:1.5;">200</span>       <span style="line-height:1.5;"><br /> </span>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> x </span>       <span style="line-height:1.5;">/</span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;">5</span>       <span style="line-height:1.5;">;<br /> </span>       <span style="line-height:1.5;">40</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">可以使用标准的javascript库</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> Math.sin(Math.PI </span>       <span style="line-height:1.5;">/</span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;">2</span>       <span style="line-height:1.5;">);<br /> </span>       <span style="line-height:1.5;">1</span>       <span style="line-height:1.5;"><br /> </span>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;color:#0000ff;">new</span>       <span style="line-height:1.5;"> Date(</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">2010/1/1</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">);<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Fri Jan 01 2010 00:00:00 GMT-0500 (EST)</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"><br /> </span>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Hello, World!</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">.replace(</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">World</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">, </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">MongoDB</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">);<br /> Hello, MongoDB</span>       <span style="line-height:1.5;">!</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">甚至可以定义javascript函数</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;color:#0000ff;">function</span>       <span style="line-height:1.5;"> factorial (n) {<br /> ... </span>       <span style="line-height:1.5;color:#0000ff;">if</span>       <span style="line-height:1.5;"> (n </span>       <span style="line-height:1.5;"><=</span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;">1</span>       <span style="line-height:1.5;">) </span>       <span style="line-height:1.5;color:#0000ff;">return</span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;">1</span>       <span style="line-height:1.5;">;<br /> ... </span>       <span style="line-height:1.5;color:#0000ff;">return</span>       <span style="line-height:1.5;"> n </span>       <span style="line-height:1.5;">*</span>       <span style="line-height:1.5;"> factorial(n </span>       <span style="line-height:1.5;">-</span>       <span style="line-height:1.5;"> </span>       <span style="line-height:1.5;">1</span>       <span style="line-height:1.5;">);<br /> ... }<br /> </span>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> factorial(</span>       <span style="line-height:1.5;">5</span>       <span style="line-height:1.5;">);<br /> </span>       <span style="line-height:1.5;">120</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">能够执行javascript确实很cool,当然这不是shell的全部功能。</p>     <ul style="line-height:20px;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;margin-left:45px;font-size:13px;">      <li>使用use命名切换数据库</li>     </ul>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> use foobar<br /> switched to db foobar</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">然后就可以查看db变量来看看当前数据库是啥</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> db<br /> foobar</span>      </div>     </div>     <ul style="line-height:20px;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;margin-left:45px;font-size:13px;">      <li>使用insert函数想collection插入document</li>     </ul>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">先创建一个本地变量叫post</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> post </span>       <span style="line-height:1.5;">=</span>       <span style="line-height:1.5;"> {</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">title</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">My Blog Post</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">,<br /> ... </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">content</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Here's my blog post.</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">,<br /> ... </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">date</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;color:#0000ff;">new</span>       <span style="line-height:1.5;"> Date()}<br /> {<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">title</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">My Blog Post</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">,<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">content</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Here's my blog post.</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">,<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">date</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Sat Dec 12 2009 11:23:21 GMT-0500 (EST)</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"><br /> }</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">然后把它插入到叫blog的collection里边去</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> db.blog.insert(post)</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">然后我们可以用find函数看看blog里边的内容</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> db.blog.find()<br /> {<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">_id</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : ObjectId(</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">4b23c3ca7525f35f94b60a2d</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">),<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">title</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">My Blog Post</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">,<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">content</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Here's my blog post.</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">,<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">date</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Sat Dec 12 2009 11:23:21 GMT-0500 (EST)</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"><br /> }</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">里边自动加了个叫"_id"的key。</p>     <ul style="line-height:20px;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;margin-left:45px;font-size:13px;">      <li>find返回collection里的书有document,如果只想查看一个使用findone<br />       <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';font-size:12px;word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">        <div>         <span style="line-height:1.5;">></span>         <span style="line-height:1.5;"> db.blog.findOne()<br /> {<br /> </span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">_id</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;"> : ObjectId(</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">4b23c3ca7525f35f94b60a2d</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">),<br /> </span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">title</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;"> : </span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">My Blog Post</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">,<br /> </span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">content</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;"> : </span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">Here's my blog post.</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">,<br /> </span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">date</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;"> : </span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">Sat Dec 12 2009 11:23:21 GMT-0500 (EST)</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;"><br /> }</span>        </div>       </div> </li>     </ul>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">find和findone都可以有查询条件,第4章查询里边会讲。</p>     <ul style="line-height:20px;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;margin-left:45px;font-size:13px;">      <li>使用update来更新document</li>     </ul>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">update函数要有至少两个参数,第一个是条件,第二个是新的document</p>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">先给post变量加一个叫comments的key,给它一个空数组做value。</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> post.comments </span>       <span style="line-height:1.5;">=</span>       <span style="line-height:1.5;"> []<br /> [ ]</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">执行更新,替换掉title是“My Blog Post”的那个document</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> db.blog.update({title : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">My Blog Post</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">}, post)</span>      </div>     </div>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;">看看结果</p>     <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;line-height:20px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">      <div>       <span style="line-height:1.5;">></span>       <span style="line-height:1.5;"> db.blog.find()<br /> {<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">_id</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : ObjectId(</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">4b23c3ca7525f35f94b60a2d</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">),<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">title</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">My Blog Post</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">,<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">content</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Here's my blog post.</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">,<br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">date</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">Sat Dec 12 2009 11:23:21 GMT-0500 (EST)</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"><br /> </span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;">comments</span>       <span style="line-height:1.5;">"</span>       <span style="line-height:1.5;"> : [ ]<br /> }</span>      </div>     </div>     <ul style="line-height:20px;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;margin-left:45px;font-size:13px;">      <li>使用remove删除document<br />       <div style="border-bottom:#cccccc 1px solid;border-left:#cccccc 1px solid;padding-bottom:5px;overflow-x:auto;overflow-y:auto;background-color:#f5f5f5;padding-left:5px;padding-right:5px;font-family:'Courier New';font-size:12px;word-break:break-all;border-top:#cccccc 1px solid;border-right:#cccccc 1px solid;padding-top:5px;" class="cnblogs_code">        <div>         <span style="line-height:1.5;">></span>         <span style="line-height:1.5;"> db.blog.remove({title : </span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">My Blog Post</span>         <span style="line-height:1.5;">"</span>         <span style="line-height:1.5;">})</span>        </div>       </div> 现在这个collection就又空了。</li>     </ul>     <p style="line-height:20px;margin:5px auto;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;font-size:13px;"><strong>3.基本数据类型</strong></p>     <ul style="line-height:20px;font-family:Verdana,Geneva,Arial,Helvetica,sans-serif;margin-left:45px;font-size:13px;">      <li>null<strong><br /> </strong>表示一个空值或者不存在的字段</li>      <li>boolean</li>      <li>32位整数<br /> shell中无法表示,javascript只支持64位浮点小数,所以会被转化为64位浮点小数。</li>      <li>64位整数<br /> 同上</li>      <li>64位浮点小数</li>      <li>字符串</li>      <li>symbol<br /> shell不支持此类型,来自数据库中的symbol类型数据会转化为字符串</li>      <li>object id<br /> 0 1 2 3     |4 5 6     |7 8   |9 10 11<br /> Timestamp|Machine | PID  |Increment</li>      <li>date</li>      <li>正则表达式</li>      <li>code</li>      <li>二进制数据</li>      <li>maximum value<br /> bson有这样一个专门的类型来表示可能的最大值,shell不支持此类型。</li>      <li>minimum value</li>      <li>undefined</li>      <li>array</li>      <li>embeded document</li>     </ul>    </div>