【原】Mongodb相關資料

Mongodb與關係型數據庫對比

Mongodb與關係型數據庫對比
因爲以前主要接觸的是關係型數據庫，因此主要將Mongodb與關係型數據庫進行對比：主要從術語、Server與Client、數據定義語言和操做語言四個方面進行比較。

1.術語

Mongodb與關係型數據庫的術語對好比下圖

關係型數據庫術語	MongoDB 術語
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.數據庫Server與Client對比

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

3.數據定義語言CREATE、ALTER、DROP比較

關係型數據庫SQL語句	MongoDB語句
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.數據操做語言CURD比較

INSERT

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

SELECT

SQL SELECT 語句	MongoDB find 語句
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語句	MongoDB update語句
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 語句	MongoDB remove語句
DELETE FROM usersWHERE status = "D"	db.users.remove( { status: "D" } )
DELETE FROM users	db.users.remove({})

學習資料

網址：

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

Mongodb官方文檔感受寫的真心不錯，推薦！