Mongodb (quick start) (I)

Data address ：

link ：https://pan.baidu.com/s/1DxgX3RCvWfaKzziHG8IHZQ
Extraction code ：3452

gitee Address

https://gitee.com/liushanshan126/mongodb-test

One 、mongdb Relevant concepts

1、mysql and mongdb contrast

2、bson（mongdb Storage structure , And json similar ）

1. Bson in , Except for the basic JSON type ：string,integer,boolean,double,null,array and object
2. mongo Special data types are also used . These types include date,object id,binary data,regular expression
   and code. Each driver implements these types in a language specific way , Check the documentation of your driver for details .
   

Two 、 Single deployment

1、 Install compressed files , And create data/db file

2、 Single machine start command

Get into bin In the folder ,cmd Console , Enter the command ：

mongod–dbpath=…\data\db

3、 ... and 、 Basic common commands

1、 establish 、 Display database

Be careful ： Create database , But this database has no collection （ surface ） When , It will only exist in memory , Only when there is a collection in the current database can it be instantiated to the disk

2、 Delete

Enter the database that needs to be deleted , And then execute

db.dropDatabase()

3 、 insert data

db.comment.insert({“articleid”:“100000”,“content”:“ It's a beautiful day , The sun is shining ”,“userid”:“1001”,“nickname”:“Rose”,“createdatetime”:newDate(),“likenum”:NumberInt(10),“state”:null})

3、 Inquire about db.document.find({},{})：document Is a table ; The first brace ： Query criteria , amount to where Later conditions ; The second brace ： Show which fields , amount to select The following query fields

for example ： db.article.findOne({articleid:‘12222’}, {userid:1, nickname:1}) Query field articleid by 12222 The data of , And only take out userid,nickname, _id( Default ) Field

4、 to update

4.1 、 General update （ Partial update $set）

db.article.update({_id:“2”},{$set:{likenum:NumberInt(889)}})

4.2 Column value increases （ Numbers + n） $inc

db.article.update({_id:“3”},{$inc:{likenum:NumberInt(1)}})

5、 Delete the document

6、 Sort sort

sort() Method can be used to specify the sorting field by parameter , And use 1 and -1 To specify how to sort , among 1 Arrange... In ascending order , and -1 It's for descending order .

db.COLLECTION_NAME.find().sort({KEY:1})

skip、limit、sort Execution order of

Follow mysql equally , Execute first sort, In execution skip, Finally, execute limit

7、 Regular expression

8、 Comparison query （ Greater than , Less than , Greater than or equal to , Less than or equal to , It's not equal to ）

9、 contain （in）, It doesn't contain （nin）

in：db.comment.find({userid:{ KaTeX parse error: Expected 'EOF', got '}' at position 19: …["1003","1004"]}̲}) nin：db.comme…nin:[“1003”,“1004”]}})

10、 Conditional connection .or and and Use

summary

Select switch database ：usearticledb
insert data ：db.comment.insert({bson data })
Query all the data ：db.comment.find();
Condition query data ：db.comment.find({ Conditions })
Query the first record that meets the criteria ：db.comment.findOne({ Conditions })
Query the first few records that meet the criteria ：db.comment.find({ Conditions }).limit( Number of pieces )
Query qualified skipped records ：db.comment.find({ Conditions }).skip( Number of pieces )
Modifying data ：db.comment.update({ Conditions },{ Revised data }) or db.comment.update({ Conditions },{ KaTeX parse error: Expected '}', got 'EOF' at end of input: …t.update({ Conditions },{ inc:{ Self increasing field : Step value }})
Delete data ：db.comment.remove({ Conditions })
Statistics query ：db.comment.count({ Conditions })
Fuzzy query ：db.comment.find({ Field name :/ Regular expressions /})
Conditional comparison operations ：db.comment.find({ Field name :{$gt: value }})

Contains the query ：db.comment.find({ Field name :{ KaTeX parse error: Expected 'EOF', got '}' at position 11: in:[ value 1, value 2]}̲}) or db.comment.f…nin:[ value 1, value 2]}})
Conditional join query ：db.comment.find({ KaTeX parse error: Expected 'EOF', got '}' at position 18: …d:[{ Conditions 1},{ Conditions 2}]}̲) or db.comment.fi…or:[{ Conditions 1},{ Conditions 2}]})

Four 、 Indexes

1、 type

Single field index 、 Composite index 、 Other indexes

2、 View index 、 establish 、 Delete

see ：db.collection.getIndexes()

establish ：
Single field index ：db.comment.createIndex({userid:1})
Composite index ：db.comment.createIndex({userid:1,nickname:-1})

Delete ：
Single delete ：db.comment.dropIndex({userid:1})
Delete all indexes ：db.collection.dropIndexes()

3、 Use index as a condition , The query field is also an index , Then do not check the set , Direct query index

5、 ... and 、java Actual operation mongodb

1、 Introduce dependencies

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/>
        <!--lookupparentfromrepository-->
    </parent>

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- Connect mongodb Dependence -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>
    </dependencies>

2、dao

3、 Entity class

4、service

package com.bear.service;

import com.bear.dao.CommentRepository;
import com.bear.pojo.Comment;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Optional;

/** * < sketch > * < Detailed description > * * @author LiuShanshan * @version $Id$ */
@Service
public class CommentService {
    
    @Resource
    private CommentRepository commentRepository;

    /** *< sketch >  increase  *< Detailed description > * @author Liushanshan * @param comment * @return void */
    public void saveComment(Comment comment){
    
        Comment save = commentRepository.save(comment);
        System.out.println(save);
    }

    //  Delete 
    public void delete(String id){
    
        commentRepository.deleteById(id);
    }

    //  Change 

    public void update (Comment comment){
    
        commentRepository.save(comment);
    }

    //  check 
    public Comment select (String id){
    
        Optional<Comment> byId = commentRepository.findById(id);
        Comment comment = byId.get();
        return comment;
    }
}

5、 Test class

@RunWith(SpringRunner.class)
@SpringBootTest(classes=MongodbApplication.class)
public class Test {
    
    @Autowired
    private CommentService commentService;

    //  preservation 
    @org.junit.Test
    public void saveTest(){
    
        Comment comment = new Comment();
        comment.setArticleid("100000");
        comment.setContent(" Test the added data ");
        comment.setCreatedatetime(LocalDateTime.now());
        comment.setUserid("1003");
        comment.setNickname(" Caesar the great ");
        comment.setState("1");
        comment.setLikenum(0);
        comment.setReplynum(0);
        commentService.saveComment(comment);
    }

    //  Inquire about 
    @org.junit.Test
    public void select(){
    
        Comment select = commentService.select("62bd78cc4e03471050ba849e");
        System.out.println(select);
    }

    //  to update 
    @org.junit.Test
    public void update(){
    
        Comment select = commentService.select("62bd78cc4e03471050ba849e");
        select.setUserid("234234234");
        commentService.update(select);
    }

    //  Delete 

}

6、 Paging condition query

6.1 Paging condition query 2.0

6.2 MongoTemplate Use （***）