Mongo/Mongoose Commands

A list of basic Mongo commands and Mongoose commands

Mongo Bash Commands

Connect to local server (In bash)

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1. activate local server port

• mongod

• activate success when we see "Waiting for connection" and port number

2. connect with mongo shell

• mongosh

If you forgot to quit the Mongod Server and close to terminal

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1. Open a new terminal

2.  sudo pkill -f mongod

3. Enter you password

Show all database

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• show dbs

Create Operation

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Create a new database

• use <database name>

Insert a data to database

• db.<database name>.insertOne(
    {
      name: "tim",
      age: 26
    }
  )

• if database does not exist, it will create one.

Insert a data with many subData (one to many relationship)

• db.<database name>.insertOne(
    {
      name: "tim",
      age: 26,
      achievement:[
        {
          title: "cap",
          year: 2021
        },
        {
          title: "gold",
          year: 2023
        }
      ]
    }
  )

Read Operation

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Find specific data

• db.<database name>.find(
    {
      name: "tim",
      age: 26
    }
  )

Find data in specific bound

• find data in database that has age > 10

• db.<database name>.find(
    {
      age: {$gt: 10}
    }
  )

Find data with specific return

• find data in database that has age > 10 and return with name and id
• 0 = do not show, 1 = show

• db.<database name>.find(
    {
      age: {$gt: 10}
    },
    {
      _id: 0,
      name: 1
    }
  )

Update Operation

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update a specific data

•  db.<database name>.updateOne(
     {
       _id: 1
     },
     {
       $set: {title: 15}
     }
   )

Delete Operation

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delete a database

1. switch to the database

•   use <database name>

2. delete the database

•   db.dropDatabase()

delete a specific data

•  db.<database name>.deleteOne(
     {
       _id: 1
     }
   )

• delete successful if return acknowledged: true, and deletedCount: 1

Mongoose commands

include npm libraries in bash in your project directory

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•  npm i mongoose

Connect to mongoDB database in nodejs

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1. require package

   •  const mongoose = require("mongoose"); 

2. connect to mongoDB database
   • connect to database with local host

   •   mongoose.connect("mongodb://localhost:27017/<database name>", { useNewUrlParser: true });

Disconnect to mongoDB database in nodejs

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•   mongoose.connection.close();

Data validation

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•   const <schema name> = new mongoose.Schema({
          name: {
            type: String,
            required: [true, "Please check your data entry, no name specified!"]
          },
          rating: {
            type: Number,
            min: 1,
            max: 10
          },
          review: String
        });

Establishing Relationships and Embedding Documents

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•   const schema1 = new mongoose.Schema({
          name: {
            type: String,
            required: [true, "Please check your data entry, no name specified!"]
          },
          rating: {
            type: Number,
            min: 1,
            max: 10
          },
          review: String
        });
        
   const schema2 = new mongoose.Schema({
        name: String,
        age: Number,
        FavouriteBook: schema1
   }); 

Create Operation

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create New Schema and Model(collection)

1.   const <schema name> = new mongoose.Schema({
       name: String,
       rating: Number,
       review: String
     });

2.   const <Model name> = mongoose.model("<Database name> without s", <schema name>);

• model name's first letter usually written in Capital letter

insert new object(document) to databse

•   const obj = new <Model name>({
      <key>: <value>,
      <key>: <value>,
      <key>: <value>
    });
    
    const obj.save();

insert many objects(documents) to database

•   const obj1 = new <Model name>({
      <key>: <value>,
      <key>: <value>,
      <key>: <value>
    });
    
    <Model name>.insertMany([obj1, obj2, obj3])
       .then(function(){
           console.log("Successfully add item list to database.");
       })
       .catch(function(err){
           console.log(err);
       });
    
    // Alternate version
    /*
    <Model name>.insertMany([obj1, obj2, obj3])
       .then(() => {
           console.log("Successfully add item list to database.");
       })
       .catch((err) => {
           console.log(err);
       });
    */

Read operation

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read all objects(documents) in database

•   <Model name>.find({})
       .then(function(<result name>){
           console.log("Successfully add item list to database.");
       })
       .catch(function(err){
           console.log(err);
       });

Update operation

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update an object(document) in database

•   <Model name>.updateOne({_id: "123123"} , {name: "newName"}, function(err){
      if(err){
        console.log(err);
      }else{
        console.log("Successfully updated the document.");
      });

Delete operation

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delete an object(document) in database

•   <Model name>.deleteOne({_id: "123123"})
      .then(function(){
            console.log("Successfully deleted item");
        })
        .catch(function(err){
            console.log(err);
        });

delete multiple objects(documents) in database

•   <Model name>.deleteMany({name: "John"})
      .then(function(){
            console.log("Successfully deleted items");
        })
        .catch(function(err){
            console.log(err);
        });