How to add new fields to mongodb with code (all)

Preface

About MongoDB See my previous article for more information ：
MongoDB Introduction to framework zero foundation

In itself MongoDB The connection is just like Mysql The same as your database
Mysql How to connect ：mysql -u -root -p（ In standard mode ）
MongoDB similar ：mongo -u root -p

The reason for adding field values
It's usually python web In the frame , stay form A field value is added to the form and written into the database （ Only the latest data has this field value ）
Field values that have no previous data can only be added through the database
The specific adding method can be added by one click in the database or script （ Both methods are similar ）

1. Add

Add field values in the database
adopt update Just add

adopt mongo Connected to the （ Distinguish version number 、 user name 、 password 、 Document collection 、 Port number, etc ）
My connection method is ：mongo Version number --host xxx -u user name -p " password " Document collection --port Port number
The link will show mongo Command entry （ similar mysql）
Add the required document collection field value in the database

At the same time, for the sake of conservatism , Through the first find Query whether there is this field

The format is as follows ：db. Document collection .find（{ Field value Dictionary }）.pretty()
The code example is as follows ：

db.manong.find({"age":18}).pretty()

After finding that the field value has a value update Update and add a field value
The format is as follows ：db.collection.update({query},{$set:{"":""}})

db.manong.update({
    "age":18},{
    $set:{
    'title':' Code the agriculture -  Research monk '}})

Re pass find Query whether there is the field value

If all data is added, the value of this field is 'title':' Code the agriculture - Research monk '
The code is as follows ：

db.manong.update({
    },{
    $set:{
    'title':' Code the agriculture -  Research monk '}})

2. Script add

It is conservative and safe to modify the script with one click
The main reason is that the terminal may make a fatal error by slightly typing the wrong command enter

The specific script only needs to be connected mongo、 Inquire about mongo Whether there is this data value （debug）、 Add new field values accordingly
（ Add this field value to all data ） The complete code is as follows ：

import datetime

from django.core.management.base import BaseCommand

#  Bring in the connection mongo Function of , Write on the outside , Don't put connection functions in your code 
from xx.common import get_mongo

class Command(BaseCommand):
    def handle(self, *args, **options):
    
    	#  Connect mongo
        mongo = get_mongo()

        values = {
    
            "$set": {
    
            	"title":" Code the agriculture -  Research monk "
            }
        }
        mongo[" aggregate "].update({
    }, values, multi=True)
		
		# debug Query display value 
        for record in mongo[" aggregate "].find():
            logger.info(record)

adopt python xx.py（ file name ） Execute the script
If the virtual environment is set, execute the script
See my article for details ：
Windows Configure virtual environment and common commands （ Graphic analysis ）

The other is ：
The script of adding this field value to a certain data is as follows ：（ Core code ）

params = {
    
    "age": 18
}
values = {
    
    "$set": {
    
        "title":" Code the agriculture -  Research monk "
    }
}
mongo[" aggregate "].update(params, values)

# debug Query display value 
for record in mongo[" aggregate "].find():
    logger.info(record)