Mongodb learning

1. install MongoDB: My next version 3.2
MongoDB Community Download | MongoDBhttps://www.mongodb.com/try/download/community2. Configure environment variables ：
C:\Program Files\MongoDB\Server\5.0\bin Add to environment variables Inside path in
3. start-up mongoDB, open cmd( Path is not related ) Input mongod

 

visit localhost:27017 On behalf of success
Custom database data Path and port number command ：mongod --dbpath Database path --port Port number ( No more than 65535)
Database client ：
-- The client is used to operate the server , Add, delete, modify and query data
-- mongo: Start client

take MongoDB Set as system service , Can start automatically in the background , No need to start manually every time
1. stay C Disk creation data Of db and log Catalog .
2. Installation directory bin There is a mongod.cfg file , Good configuration data and log The catalog of
3. Open command line window as Administrator
4. Execute the following command ：
    4.1 stay C Disk creation data/db 
    4.2 perform sc.exe create MongoDB binPath="\"C:\Program Files\MongoDB\Server\3.2\bin\mongod.exe"  --service --config=\"C:\Program Files\MongoDB\Server\3.2\mongod.cfg"" DisplayName= "MongoDB" start= "auto" 
Then close all cmd Can also access , It means success .

Basic instructions ：
show dbs,show databases  Display all current databases
db  Indicates the current database
show collections Show all collections in the database
Database CRUD( Additions and deletions ) operation
Insert a document into the database ：
db.stus.insert<<name:"sunwukong",age:18,gender:"male">>;
Successfully returns WriteResult<<"nlnserted":1>>
db.stus.find()  Query the data in the document
db.stus.find({_id:"hello"}) lookup id by hello Documents
findOne() Return an object ,find It returns an array
db.stus.find({num:{$gt:500}}) lookup num Greater than 500 Of
db.stus.find({num:{$eq:500}}) lookup num be equal to 500 Of
db.stus.find({num:{$lt:500}}) lookup num Less than 500 Of
db.stus.find({num:{$gt:40,$lt:50}}) lookup num Greater than 40 Less than 50 Of
db.stus.find().limit(10);  Before display 10 Data
db.stus.find().skip(10).limit(10); skip= Page number -1,limit( Number of entries per page ),mongoDB Can adjust skip and limit The order of , So the order doesn't matter skip(10).limit(10) According to the first 11 To 20 Numbers
db.stus.find({}).sort({sal:1,empno:-1});  sort() It can be used to specify the collation of documents
1 Expressing ascending order -1 Representation of descending order
db.stus.find({},{ename:1,_id:0,sal:1}); The position of the second parameter sets the displayed field
Modify to the database ：
By default, the old object is replaced with the new object , hold name by 33 The whole object of , There's only one property age by 2：db.stus.update({name:"33",age:2});
Modifying is not replacing the entire object , The first {} It's a matching condition ：
db.stus.update({"_id":ObjectId("59c219689410bcc0709")},
{$set:{gender:" male ",address:" Liusha River "}})
unset Used to delete specified attributes ：
db.stus.updateMany Modify multiple ,update Only one is changed by default
db.stus.updateOne To modify a
Delete... To the database ：
db.stus.remove(), Must pass reference , Delete all eligible documents , Multiple... Are deleted by default , The second parameter is true, Only one... Is deleted , If you don't pass the parameters , Will empty the collection ( Slightly poor performance , Because it will match before deleting , If you want to empty, just empty the collection db.stus.drop()).
db.stus.deleteOne() Delete one that meets the conditions
db.stus.deleteMany() Delete multiple matching
mongoose The benefits of ：
You can create a schema structure for a document (Schema)
Objects in the model can be / Document validation
Data can be converted to an object model through type conversion
Middleware can be used to apply business logic hooks
Than Node Native MongoDB Easier to drive
1. Download and install Mongoose
  stay mongodb Graphical tools (mongodbmanagerpro) Carry out orders ：
npm i mongoose --save
2. Introduce in the project mongoose
 var mongoose=require("mongoose")
3. Connect mongodb database
Example ：

var mongoose=require{"mongoose"};
mongoose.connect("mongodb://127.0.0.1/mongoose_test",{udrMonhoVlirny:true});

mongoose.connection.once("open",function(){
  console.log(" Database connection successful ~~~")
})
mongoose.connection.once("close",function(){
  console.log(" Database disconnected ~~~")
})

// disconnect 
mongoose.disconnect();

establish Schema:

var mongoose=require{"mongoose"};
mongoose.connect("mongodb://127.0.0.1/mongoose_test",{udrMonhoVlirny:true});

mongoose.connection.once("open",function(){
  console.log(" Database connection successful ~~~")
})

var Schema=mongoose.Schema;
var stuSchema=new Schema({
   name:String,
   age:Number,
   gender:{
     type:String,
     default:"female"
   },
   address:String
})
// adopt Schema To create Model
//Model Represents a collection in a database , adopt Model To operate on the database 
//mongoose.model(modelName,schema)
//modelName, Is the name of the set to be mapped 
var stuModel=mongoose.model("student",stuSchema)
stuModel.create({
    name:" The Monkey King ",
    age:18,
    gender:"male",
   address:" Huaguoshan "
},function(err){
   if(!err){
    console.log(" Insert the success ~~~~");
   }
})

stuModel.find({name:" Tang's monk 123"},function(err,docs){
  if(!err){
   // It's an array , If only one field .docs[0].name
    console.log(docs)
  }
})

// It means as long as name and age Field shows , Don't _id  This field 
stuModel.find({},"name age -_id",function(err,docs){
  if(!err){
    console.log(docs)
  }
})

// It means as long as name and age Field shows , Don't _id  This field 
stuModel.find({},"name age -_id",{skip:3,limit:1},function(err,docs){
  if(!err){
    console.log(docs)
  }
})
// Return an object , Is not an array 
stuModel.findOne({},function(err,doc){
  if(!err){
    console.log(docs)
  }
})
//59c4c3cf4e5483191467 yes id Value 
stuModel.findById("59c4c3cf4e5483191467",function(err,doc){
  if(!err){
    console.log(docs)
  }
})

update:
 

stuModel.findOne({},function(err,doc){
  if(!err){
    doc.update({$set:{age:28}},function(err){
    if(!err){
     console.log(" Modification successful !")
    }
   })
   // Another way 
    doc.age=18
    doc.save();

   // Delete 
   doc.remove(function(err){
     if(!err){
        console.log(" Delete successful ~~~")
     }
   })
  }
})