【原】Mongodb相关资料

Mongodb与关系型数据库对比

Mongodb与关系型数据库对比

由于之前主要接触的是关系型数据库，所以主要将Mongodb与关系型数据库进行对比：主要从术语、Server与Client、数据定义语言和操作语言四个方面进行比较。

1.术语

Mongodb与关系型数据库的术语对比如下图

关系型数据库术语	MongoDB 术语
database	database
table	collection
row	document or BSON document
column	field
index	index
table joins	embedded documents and linking
primary key Specify any unique column or column combination as primary key.	primary key In MongoDB, the primary key is automatically set to the _id field.
aggregation (e.g. group by)	aggregation pipeline See the SQL to Aggregation Mapping Chart.

2.数据库Server与Client对比

type	MongoDB MySQL	Oracle	Informix	DB2
Database Server	mongod	mysqld	oracle	IDS
Database Client	mongo	mysql	sqlplus	DB-Access

3.数据定义语言CREATE、ALTER、DROP比较

关系型数据库SQL语句	MongoDB语句
CREATE TABLE users ( id MEDIUMINT NOT NULL AUTO_INCREMENT,user_id Varchar(30),age Number,status char(1),PRIMARY KEY (id))	Implicitly created on first insert() operation. The primary key_id is automatically added if _id field is not specified. db.users.insert( { user_id: "abc123", age: 55, status: "A" } ) However, you can also explicitly create a collection: db.createCollection("users")
ALTER TABLE usersADD join_date DATETIME	Collections do not describe or enforce the structure of its documents; i.e. there is no structural alteration at the collection level. However, at the document level, update() operations can add fields to existing documents using the $set operator. db.users.update( { }, { $set: { join_date: new Date() } }, { multi: true })
ALTER TABLE usersDROP COLUMN join_date	Collections do not describe or enforce the structure of its documents; i.e. there is no structural alteration at the collection level. However, at the document level, update() operations can remove fields from documents using the $unset operator. db.users.update( { }, { $unset: { join_date: "" } }, { multi: true })
CREATE INDEX idx_user_id_ascON users(user_id)	db.users.createIndex( { user_id: 1 } )
CREATE INDEX idx_user_id_asc_age_descON users(user_id, age DESC)	db.users.createIndex( { user_id: 1, age: -1 } )
DROP TABLE users	db.users.drop()

4.数据操作语言CURD比较

INSERT

SQL INSERT 语句	MongoDB insert语句
INSERT INTO users(user_id,age,status)VALUES ("bcd001",45,"A")	db.users.insert( { user_id: "bcd001", age: 45, status: "A" })

SELECT

SQL SELECT 语句	MongoDB find 语句
SELECT *FROM users	db.users.find()
SELECT id,user_id,statusFROM users	db.users.find( { }, { user_id: 1, status: 1 })
SELECT user_id, status FROM users	db.users.find( { }, { user_id: 1, status: 1, _id: 0 })
SELECT *FROM usersWHERE status = "A"	db.users.find( { status: "A" })
SELECT user_id, statusFROM usersWHERE status = "A"	db.users.find( { status: "A" }, { user_id: 1, status: 1, _id: 0 })
SELECT *FROM usersWHERE status != "A"	db.users.find( { status: { $ne: "A" } })
SELECT *FROM usersWHERE status = "A"AND age = 50	db.users.find( { status: "A", age: 50 })
SELECT *FROM usersWHERE status = "A"OR age = 50	db.users.find( { $or: [ { status: "A" } , { age: 50 } ] })
SELECT *FROM usersWHERE age > 25	db.users.find( { age: { $gt: 25 } })
SELECT *FROM usersWHERE age < 25	db.users.find( { age: { $lt: 25 } })
SELECT *FROM usersWHERE age > 25AND age <= 50	db.users.find( { age: { $gt: 25, $lte: 50 } })
SELECT *FROM usersWHERE user_id like "%bc%"	db.users.find( { user_id: /bc/ } )
SELECT *FROM usersWHERE user_id like "bc%"	db.users.find( { user_id: /^bc/ } )
SELECT *FROM usersWHERE status = "A"ORDER BY user_id ASC	db.users.find( { status: "A" } ).sort( { user_id: 1 } )
SELECT *FROM usersWHERE status = "A"ORDER BY user_id DESC	db.users.find( { status: "A" } ).sort( { user_id: -1 } )
SELECT COUNT(*)FROM users	db.users.count() or db.users.find().count()
SELECT COUNT(user_id)FROM users	db.users.count( { user_id: { $exists: true } } ) or db.users.find( { user_id: { $exists: true } } ).count()
SELECT COUNT(*)FROM users WHERE age > 30	db.users.count( { age: { $gt: 30 } } ) or db.users.find( { age: { $gt: 30 } } ).count()
SELECT DISTINCT(status)FROM users	db.users.distinct( "status" )
SELECT *FROM usersLIMIT 1	db.users.findOne() or db.users.find().limit(1)
SELECT *FROM usersLIMIT 5SKIP 10	db.users.find().limit(5).skip(10)
EXPLAIN SELECT *FROM usersWHERE status = "A"	db.users.find( { status: "A" } ).explain()

UPDATE

SQL Updatey语句	MongoDB update语句
UPDATE usersSET status = "C"WHERE age > 25	db.users.update( { age: { $gt: 25 } }, { $set: { status: "C" } }, { multi: true })
UPDATE usersSET age = age + 3WHERE status = "A"	db.users.update( { status: "A" } , { $inc: { age: 3 } }, { multi: true })

DELETE

SQL Delete 语句	MongoDB remove语句
DELETE FROM usersWHERE status = "D"	db.users.remove( { status: "D" } )
DELETE FROM users	db.users.remove({})

学习资料

网址：

1. 官方Tutorial
2. 官方 Document
3. Tutorial
4. Java操作Mongodb

Mongodb官方文档感觉写的真心不错，推荐！