[转]Mongodb 与sql 语句对照

http://www.cnblogs.com/cxd4321/archive/2011/05/31/2064843.html

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:

	MongoDB	Mysql
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 title= 'foobar'
查询数量	movies.Find(new Document { { "title", "测试2" } }).Documents.Count();	SELECT COUNT(*) FROM movies WHERE `title` = 'foobar'
数量范围查询	1, movies.Find(new Document().Add("$where", new Code("this.num > 50"))); 2, movies.Find(new Document().Add("num", new Document().Add("$gt",50))); ($gt : > ; $gte : >= ; $lt : < ; $lte : <= ; $ne : !=) 3,movies.Find("this.num > 50"); 4,movies.Find(new Document().Add("$where",new Code("function(x){ return this.num > 50};")));	select * from movies where num > 50
分页查询	movies.Find(new Document()).Skip(10).Limit(20);	SELECT * FROM movies limit 10,20
查询排序语句	movies.Find(new Document()).Sort(new Document() { { "num", -1 } });	SELECT * FROM movies ORDER BY num DESC
查询指定字段	movies.Find(new Document().Add("num", new Document().Add("$gt", 50)), 10, 0, new Document() { { "title", 1 } });	select title from movies where num > 50
插入语句	movies.Insert(new Document() { { "title", "测试" }, { "resuleData", DateTime.Now } });	INSERT INOT movies (`title`, `reauleDate`) values ('foobar',25)
删除语句	movies.Remove(new Document() { { "title", "Hello Esr" } });	DELETE * FROM movies
更新语句	movies.Update(new Document() { { "title", "测试2" } } , new Document() { { "title", "测试11111" } });	UPDATE movies SET `title` = ‘测试1111’ WHERE `title` = '测试1111'
Linq查询	(from item in db.GetCollection("movies").Linq() where ((string)item["title"]).StartsWith("Esr") select item);	select * from movies where title like ‘%Esr’

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.

sql语法和MongoDB语法的对应关系

SQL Statement	Mongo Query Language Statement
CREATE TABLE USERS (a Number, b Number)	db.createCollection( "mycoll", {capped:true , size:100000})
INSERT INTO USERS VALUES(1,1)	db.users.insert({a:1,b:1})
SELECT a,b FROM users	db.users.find({}, {a:1,b:1})
SELECT * FROM users	db.users.find()
SELECT * FROM users WHERE age=33	db.users.find({age:33})
SELECT a,b FROM users WHERE age=33	db.users.find({age:33}, {a:1,b:1})
SELECT * FROM users WHERE age=33 ORDER BY name	db.users.find({age:33}).sort({name:1})
SELECT * FROM users WHERE age>33	db.users.find({'age':{$gt:33}})})
SELECT * FROM users WHERE age<33	db.users.find({'age':{$lt:33}})})
SELECT * FROM users WHERE name LIKE "%Joe%"	db.users.find({name:/Joe/})
SELECT * FROM users WHERE name LIKE "Joe%"	db.users.find({name:/^Joe/})
SELECT * FROM users WHERE age>33 AND age<=40	db.users.find({'age':{$gt:33,$lte:40}})})
SELECT * FROM users ORDER BY name DESC	db.users.find().sort({name:-1})
CREATE INDEX myindexname ON users(name)	db.users.ensureIndex({name:1})
CREATE INDEX myindexname ON users(name,ts DESC)	db.users.ensureIndex({name:1,ts:-1})
SELECT * FROM users WHERE a=1 and b='q'	db.users.find({a:1,b:'q'})
SELECT * FROM users LIMIT 10 SKIP 20	db.users.find().limit(10).skip(20)
SELECT * FROM users WHERE a=1 or b=2	db.users.find( { $or : [ { a : 1 } , { b : 2 } ] } )
SELECT * FROM users LIMIT 1	db.users.findOne()
EXPLAIN SELECT * FROM users WHERE z=3	db.users.find({z:3}).explain()
SELECT DISTINCT last_name FROM users	db.users.distinct('last_name')
SELECT COUNT(*y) FROM users	db.users.count()
SELECT COUNT(*y) FROM users where AGE > 30	db.users.find({age: {'$gt': 30}}).count()
SELECT COUNT(AGE) from users	db.users.find({age: {'$exists': true}}).count()
UPDATE users SET a=1 WHERE b='q'	db.users.update({b:'q'}, {$set:{a:1}}, false, true)
UPDATE users SET a=a+2 WHERE b='q'	db.users.update({b:'q'}, {$inc:{a:2}}, false, true)
DELETE FROM users WHERE z="abc"	db.users.remove({z:'abc'});