zhangxinba 发表于 2018-10-27 12:12:10

Mongodb 与sql 语句对照

Mongodb 与sql 语句对照
  此处用mysql中的sql语句做例子,C# 驱动用的是samus,也就是上文中介绍的第一种.
  引入项目MongoDB.dll
//创建Mongo连接var mongo = new Mongo("mongodb://localhost");mongo.Connect();//获取一个数据库,如果没有会自动创建一个var db = mongo.GetDatabase("movieReviews");//创建一个列表,并为这个列表创建文档var movies = db.GetCollection("movies");  连接没问题之后,现在让我们用mysql 与mongodb的一些语句做下对比:
MongoDBMysql查询全部movies.find(new Document())SELECT * FROM movies条件查询movies.Find(new Document { { "title", "Hello Esr" } });SELECT * FROM movies WHERE>  2, movies.Find(new Document().Add("num",new Document().Add("$gt",50)));
  ($gt : > ; $gte : >= ; $lt : < ; $lte :50&quot;);
  4,movies.Find(new Document().Add(&quot;$where&quot;,new Code(&quot;function(x){ return this.num > 50};&quot;)));
select * from movies where num > 50分页查询movies.Find(new Document()).Skip(10).Limit(20);SELECT * FROM movieslimit 10,20查询排序语句movies.Find(new Document()).Sort(new Document() { { &quot;num&quot;, -1 } });SELECT * FROM movies ORDER BY num DESC查询指定字段movies.Find(new Document().Add(&quot;num&quot;, new Document().Add(&quot;$gt&quot;, 50)), 10, 0, new Document() { { &quot;title&quot;, 1 } });select>movies.Update(new Document() { { &quot;title&quot;, &quot;测试2&quot; } }  , new Document() { { &quot;title&quot;, &quot;测试11111&quot; } });
UPDATE movies SET `title` = ‘测试1111’ WHERE `title` = '测试1111'Linq查询  (from item in db.GetCollection(&quot;movies&quot;).Linq()
  where ((string)item[&quot;title&quot;]).StartsWith(&quot;Esr&quot;)
  select item);
select * from movies where>这里只举出了几个比较典型的例子,可以这么说,只要mysql可以完成的sql语句,在mongodb里面都可以实现.

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