mongodb 简单学习使用

1.  service mongodb start/stop/restart

2.  command:

 mongo  connet to mongodb instance

 db.help()

 db.stats()

//database

 show dbs

 use test

 db.movie.insert({"name":"tutorials point"})

use test;

db.dropDatabase();

//collection

use test

db.createCollection("mycollection1")

show collections

db.createCollection("mycol", { capped : true, autoIndexId : true, size : 

   6142800, max : 10000 } )

In MongoDB, you don't need to create collection. MongoDB creates collection automatically, when you insert some document   

use test

db.mycollection1.drop()

//insert to:

db.movie.insert({name:'tutorials point2',

                 title:'title2'

               })

db.movie.insert({ "_id": ObjectId("5982df3f468ac80e8f771b02"),

                 name: 'tutorials point3',

                 title:'title3'

               })  

 

db.movie.insert({name:'tutorials point4',

                 title:'title4'

               })             

ObjectId 长度为24， 否则报错;

使用insert, ObjectId重复时，会报错

_id is 12 bytes hexadecimal number unique for every document in a collection. 12 bytes are divided as follows −

_id: ObjectId(4 bytes timestamp, 3 bytes machine id, 2 bytes process id, 

   3 bytes incrementer)

if we don't specify the _id parameter, then MongoDB assigns a unique ObjectId for this document.

 insert multiple documents: you can pass an array of documents in insert() command
(1)
db.movie.insert([
  {
     title: 'MongoDB Overview', 
     description: 'MongoDB is no sql database',
     by: 'tutorials point',
     url: 'http://www.tutorialspoint.com',
     tags: ['mongodb', 'database', 'NoSQL'],
     likes: 100
  },

  {
     title: 'NoSQL Database', 
     description: 'NoSQL database doesn't have tables',
     by: 'tutorials point',
     url: 'http://www.tutorialspoint.com',
     tags: ['mongodb', 'database', 'NoSQL'],
     likes: 20, 
     comments: [

        {
           user:'user1',
           message: 'My first comment',
           dateCreated: new Date(2013,11,10,2,35),
           like: 0 
        }
     ]
  }
])
(2)
db.movie.save(document)

 db.movie.insert({ "_id": ObjectId("5982df3f468ac80e8f771b02"),

                 name: 'tutorials point5',

                 title:'title5'

               }) 

   

               
 db.movie.save({ "_id": ObjectId("5982df3f468ac80e8f771b02"),

                 name: 'tutorials point5',

                 title:'title5'

               }) 

       db.movie.insert({ "_id": ObjectId("5982df3f468ac80e8f771b03"),

                 name: 'tutorials point6',

                 title:'title6'

               }) 

               

           db.movie.insert({ "_id": ObjectId("5982df3f468ac80e8f771b04"),

                 name: 'tutorials point7',

                 title:'title7',

                 esay: 1

               })  

             db.movie.insert({ "_id": ObjectId("dalldldla"),

                 name: 'tutorials point7',

                 title:'title7',

                 esay: 1

               })                      

     IF _id exists, insert  will have error , but save will success because it will override the orginal document.

(3) the difference between (1) and (2)

If you don't specify _id in the document then save() method will work same as insert() method. If you specify _id then it will replace whole data of document containing _id as specified in save() method

//Query

use test

db.movie.find().pretty()

db.movie.findOne().pretty()

//Query partional fields:

db.movie.find({},{"title":1,_id:0}) 

db.movie.find({},{"name":1,title:1,_id:0})

1 is used to show the field while 0 is used to hide the fields

db.movie.find({},{"name":1,_id:0}).limit(3).skip(1)

//sort 1 asc -1 desc

db.movie.find({},{"name":1,_id:0}).sort({"name": 1})

//update 

update() and save() methods are used to update document into a collection

//delete

db.movie.remove(DELLETION_CRITTERIA, justOne)

db.movie.remove({title:'title7'}, 1)

//index:

db.movie.createIndex({"name": 1}) 

object Id 详解： http://www.cnblogs.com/xjk15082/archive/2011/09/18/2180792.html
mongodb 学习文档：
http://docs.mongoing.com/manual-zh/tutorial/query-documents.html  中文社区
https://github.com/mongodb/mongo-java-driver https://www.tutorialspoint.com/mongodb/mongodb_java.htm 资料有点旧