MongoDB 基础使用

李岩的MongoDB学习笔记也是不错的参考资料。http://liyanblog.cn/tags/Nosql/3

MongoDB 基础使用

$./mongod   启动Mongodb

$./mongo 连接Mongodb 默认是localhost

$./use 数据库名称  通知此会话将使用该数据库

$./show dbs 列出所有数据库

Mongodb不需要我们创建数据库或者集合.在你插入数据的时候会自动创建相关的数据库跟集合.

1) 创建

CREATE TABLE USERS (a Number, b Number)

（隐式，但也可以显式创建，例如一个封顶集合）

> # mongo shell

> db.createCollection(“mycoll”, {capped:true, size:100000})

> show collections

如果驱动支持，还可以

> db.runCommand( {createCollection:”mycoll”, capped:true, size:100000} )

(2) 插入

INSERT INTO USERS VALUES(1,1)

> db.users.insert({a:1,b:1})

(3) 查询

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}})

> db.users.find({age:{$gt:33}})

SELECT * FROM users WHERE age<33

> db.users.find({‘age’:{$lt:33}})

> db.users.find({age:{$lt:33}})

SELECT * FROM users WHERE a=1 and b=’q’

> db.users.find({a:1,b:’q'})

(4) 更新（20110311更新：包括删除？）

UPDATE users SET a=1 WHERE b=’q’

> db.users.update({b:’q'}, {$set:{a:1}}, false, true)

(5) 索引

CREATE INDEX myindexname ON users(name)

> db.users.ensureIndex({name:1})

EXPLAIN SELECT * FROM users WHERE z=3

> db.users.find({z:3}).explain()

(6) 集合函数，排序和分页和其它查询

SELECT * FROM users ORDER BY name DESC

> db.users.find().sort({name:-1})

SELECT * FROM users LIMIT 10 SKIP 20

> db.users.find().limit(10).skip(20)

SELECT * FROM users LIMIT 1

> db.users.findOne()

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()

更详细的用法见手册

http://www.mongodb.org/display/DOCS/Manual

转自：http://www.iblue.cc/category/mongodb/、