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MongoDB基础--查询、索引与聚合

时间：2021-07-01 10:21:17 帮助过：4人阅读

=({"name": "peter", "position": "teacher"})
  • { "name" : "peter", "position" : "teacher" }
  • > db.shiyanlou.insert(doc)
  • > doc1=({"name": "tom", "position": "student"})
  • { "name" : "tom", "position" : "student" }
  • > db.shiyanlou.insert(doc1)
    • 2，查询语句: db.collection_name.find(param):
    1. <ol class="linenums" style="padding-left: 0px;"><li style="list-style-type: none; padding-left: 0px;" class="L0"><code class="language-c"><span class="pun">></span><span class="pln"> db</span><span class="pun">.</span><span class="pln">shiyanlou</span><span class="pun">.</span><span class="pln">find</span><span class="pun">()</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L1"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1cca30df8c25bf44dd7"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"peter"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L2"><code class="language-c"><span class="pln"> </span><span class="str">"teacher"</span><span class="pln"> </span><span class="pun">}</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L3"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1e9a30df8c25bf44dd8"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"tom"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L4"><code class="language-c"><span class="pln">student</span><span class="str">"</span><span class="pln"> </span><span class="pun">}</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L5"><code class="language-c"><span class="pun">></span><span class="pln"> </span></code></li></ol>
        -1，条件操作符：
        
    • (>) 大于 - \$gt #greate
    • (<) 小于 - \$lt #low
    • (>=) 大于等于 - \$gte #equal
    • (<= ) 小于等于 - \$lte
        -2，type 
    • 双精度型-1
    • 字符串-2
    • 对象-3
    • 数组-4
    • 二进制数据-5
    • 对象ID-7
    • 布尔类型-8
    • 数据-9
    • 空-10
    • 正则表达式-11
    • JS代码-13
    • 符号-14
    • 有作用域的JS代码-15
    • 32位整型数-16
    • 时间戳-17
    • 64位整型数-18
    • Min key-255
    • Max key-127

    1. <ol class="linenums" style="padding-left: 0px;"><li style="list-style-type: none; padding-left: 0px;" class="L0"><code class="language-c"><span class="pln"> db</span><span class="pun">.</span><span class="pln">shiyanlou</span><span class="pun">.</span><span class="pln">find</span><span class="pun">({</span><span class="str">"name"</span><span class="pun">:</span><span class="pln"> </span><span class="pun">{</span><span class="pln">$type</span><span class="pun">:</span><span class="lit">2</span><span class="pun">}})</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L1"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1cca30df8c25bf44dd7"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"peter"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L2"><code class="language-c"><span class="pln"> </span><span class="str">"teacher"</span><span class="pln"> </span><span class="pun">}</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L3"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1e9a30df8c25bf44dd8"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"tom"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L4"><code class="language-c"><span class="pln">student</span><span class="str">" }</span></code></li></ol>
    -3，limit : 读取指定数量的记录
    1. <ol class="linenums" style="padding-left: 0px;"><li style="list-style-type: none; padding-left: 0px;" class="L0"><code class="language-c"><span class="pun">></span><span class="pln"> db</span><span class="pun">.</span><span class="pln">shiyanlou</span><span class="pun">.</span><span class="pln">find</span><span class="pun">().</span><span class="pln">limit</span><span class="pun">(</span><span class="lit">1</span><span class="pun">)</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L1"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1cca30df8c25bf44dd7"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"peter"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L2"><code class="language-c"><span class="pln"> </span><span class="str">"teacher"</span><span class="pln"> </span><span class="pun">}</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L3"><code class="language-c"><span class="pun">></span><span class="pln"> </span></code></li></ol>
    -4，skip：读取时跳过指定数据记录
    1. <ol class="linenums" style="padding-left: 0px;"><li style="list-style-type: none; padding-left: 0px;" class="L0"><code class="language-c"><span class="pun">></span><span class="pln"> db</span><span class="pun">.</span><span class="pln">shiyanlou</span><span class="pun">.</span><span class="pln">find</span><span class="pun">().</span><span class="pln">limit</span><span class="pun">(</span><span class="lit">1</span><span class="pun">).</span><span class="pln">skip</span><span class="pun">(</span><span class="lit">2</span><span class="pun">)</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L1"><code class="language-c"><span class="pun">></span><span class="pln"> db</span><span class="pun">.</span><span class="pln">shiyanlou</span><span class="pun">.</span><span class="pln">find</span><span class="pun">().</span><span class="pln">limit</span><span class="pun">(</span><span class="lit">1</span><span class="pun">).</span><span class="pln">skip</span><span class="pun">(</span><span class="lit">1</span><span class="pun">)</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L2"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1e9a30df8c25bf44dd8"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"tom"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L3"><code class="language-c"><span class="pln">student</span><span class="str">" }</span></code></li></ol>
    -5，sort 排序 1 表示升序，-1表示降序
    1. <ol class="linenums" style="padding-left: 0px;"><li style="list-style-type: none; padding-left: 0px;" class="L0"><code class="language-c"><span class="pln"> db</span><span class="pun">.</span><span class="pln">shiyanlou</span><span class="pun">.</span><span class="pln">find</span><span class="pun">().</span><span class="pln">sort</span><span class="pun">({</span><span class="str">"name"</span><span class="pun">:</span><span class="pln"> </span><span class="lit">1</span><span class="pun">})</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L1"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1cca30df8c25bf44dd7"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"peter"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L2"><code class="language-c"><span class="pln"> </span><span class="str">"teacher"</span><span class="pln"> </span><span class="pun">}</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L3"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1e9a30df8c25bf44dd8"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"tom"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L4"><code class="language-c"><span class="pln">student</span><span class="str">"</span><span class="pln"> </span><span class="pun">}</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L5"><code class="language-c"><span class="pun">></span><span class="pln"> db</span><span class="pun">.</span><span class="pln">shiyanlou</span><span class="pun">.</span><span class="pln">find</span><span class="pun">().</span><span class="pln">sort</span><span class="pun">({</span><span class="str">"name"</span><span class="pun">:-</span><span class="lit">1</span><span class="pun">})</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L6"><code class="language-c"><span class="pun">{</span><span class="pln"> </span><span class="str">"_id"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="typ">ObjectId</span><span class="pun">(</span><span class="str">"5559d1e9a30df8c25bf44dd8"</span><span class="pun">),</span><span class="pln"> </span><span class="str">"name"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"tom"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"position"</span><span class="pln"> </span><span class="pun">:</span><span class="pln"> </span><span class="str">"</span></code></li><li style="list-style-type: none; padding-left: 0px;" class="L7"><code class="language-c"><span class="pln">student</span><span class="str">" }</span></code></li></ol>
    3，索引： db.collection_name.ensureIndex()

    ensureIndex()的可选参数：

    参数类型描述
    backgroundBoolean建立索引要不要阻塞其他数据库操作，默认为false
    uniqueBoolean建立的索引是否唯一，默认false
    namestring索引的名称，若未指定，系统自动生成
    dropDupsBoolean建立唯一索引时，是否删除重复记录，默认flase
    sparseBoolean对文档不存在的字段数据不启用索引，默认false
    expireAfterSecondsinteger设置集合的生存时间，单位为秒
    vindex version索引的版本号
    weightsdocument索引权重值，范围为1到99999
    default-languagestring默认为英语
    language_overridestring默认值为 language










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