Basics of MongoDB Entry DML

Objective:

This article mainly records the DML operations of the main MongoDB Collection.

The Collection name in the second article is Yourcoll, and each operation initially contains two data

{    "_id": ObjectId ("5438df36309dca34635d4460"),    "username":"name1",    "Mail":"Name1@abc. com"},{    "_id": ObjectId ("5438df40309dca34635d4461"),    "username":"name2",    "Mail":"[email protected]",    " Age": -}

A, C

• Db.collection.insert ()
  

  Db.yourcoll. Insert ({    username: "Mayj",    Mail: "Test@abc. com"})

• Db.collection.save ()
  

  Db.yourcoll. Save ({    username: "Mayj",    Mail: "Test@abc. com"})

  Note:save operation if the document contains a primary key (_ID), to determine whether the primary key exists, if present, update the original record, if not present, insert a new record. The difference between insert and save is that if a document contains a primary key (_id) and exists, it does not handle processing and returns an error.

Second, R

• Db.collection.find ()
  • Querying All records
    

    Db.yourColl.find ();

    Equivalent to MySQL

    Select *  from Yourcoll;

  • Querying distinct duplicate data for a column
    

    Db.yourcoll. distinct

    Equivalent to MySQL

    Select  from

  • Querying the AGE=28 data
    

    Db.yourColl.find ({    ,})

    Equivalent to MySQL

    Select *  from where = ;

  • Query Age >20 data
    

     db.yourcoll.find ({age: {$gt:  20   

    Equivalent to MySQL

      *  from  yourcoll where  Age > 20 ; 

  • Query Age >=20 data
    

     db.yourcoll.find ({age: {$gte:  20   

    Equivalent to MySQL

      *  from  yourcoll where  Age >=  20 ;

  • Query Age >=20 and age < 30 data
    

     db.yourcoll.find ({age: {$gte:  20 , $lt: }})  

    Equivalent to MySQL

     select  *  from  yourcoll where  Age >=  20  and  age <  30 ;   

  • query for data in mail that contains ABC
    

     db.yourcoll.find ({mail:  / Abc/i   

    Equivalent to MySQL

     select  *  from  yourcoll like " Span style= "color: #808080;" >%  abc%  "; 

  • query username for data that begins with name
    

     db.yourcoll.find ({mail:  /^  abc/ i})  

    Equivalent to MySQL

     select  *  from  yourcoll like " Span style= "color: #808080;" >%^  abc%  "; 

  • query username =name1,mail [email protected] Data
    

     db.yourcoll.find ({ Username: "Name1", Mail: "name1   @abc  .com "})  

    Equivalent to MySQL

     select   from  yourcoll where  username Span style= "color: #808080;" >=  "name1" and  mail =  "Name1 @abc . com "; 

  • Querying data for the specified column username and mail
    

    Db.youColl.find ({    },{    username:true,    1})

    Equivalent to MySQL

    Select  from Yourcoll;

    Where true can be replaced by 1.

  • By username ascending, mail descending order
    

    Db.yourColl.find ({}). Sort ({username:1, mail:-1})

    Equivalent to MySQL

    Select *  from Order  by ASC DESC;

  • Query 1-2 Data
    

     db.yourColl.find ({}). Limit (2 ). Skip (1 ) 

    Equivalent to MySQL

     select  *  from  yourcoll limit Span style= "color: #800000; Font-weight:bold; " >1 , 1    

  • Query username = name1 or username =name2 data

     db.yourcoll.find ({$  
           
            or : 
            [ 
            {username: "Name1"}, {username: " Name2 "}  
              
            })  
           

    Equivalent to MySQL

     select  *  from  yourcoll = " Name1 "or  username = " name2 "; 

  • Query the number of records that match the criteria
    

    Db.collect1.find ({}). Count ()

    Equivalent to MySQL

    Select Count (* from Yourcoll

• Db.collection.findOne ()
  
  
• Db.collection.findAndModify ()

Three, U

• Db.collection.update ()
  
  • Update username = Name2 User has an age of $
    

     db.yourcoll.  set   30 False, 
     True)  

    equals MySQL

     update  yourcoll =  30  where  username =  "name2"; 

  • Update username = Name2 User's age is age +
    

     db.yourcoll. Update   set   30 False, 
     True)  

    equals MySQL

     update  yourcoll =  Age Span style= "color: #808080;" >+  30  where  Username =  "name2"; 

  • Update username = Name2 User's username = Name3 Age is age + 30
    

    Db.yourcoll. Update (    {        username: "Name2"    },    {        $set: {            $        },        $inc: {            username: "Name3"        }    }, False, True)

    Equivalent to MySQL

    Update Set = +  - = where = "Name2";

IV, D

• Db.collection.remove ()
  • Delete username = Name3 Records
    

    Db.yourColl.remove ({  username: "Name3"})

    Equivalent to MySQL

    Delete  from where = "Name3";

Wu, Rud

• Db.collection.findAndModify () & Db.collection.runCommond ()

•  db.users.findandmodify ({query: {age: {$gte:  25   - 1   update : {$set : {name:  " a2   ' }, $inc: {age: 2  }} , remove:true}); 

  Db.runcommand ({     findandmodify: "Users",          1},      Update: {$set'a2'2}},     

  Parametersdetailed default ValuesQueryQuery filter condition {} Sortif multiple documents conform to the query filter criteria, the first-ranked object is selected in the arrangement specified by the parameter, and the object is manipulated {} RemoveIf True, the selected object will be deleted before returning n /AUpdatea Modifier object n /aNewIf True, the modified object is returned instead of the original object. In the delete operation, the parameter is ignored. false

External resource Links:

MongoDB CRUD Introduction

Basics of MongoDB Entry DML