Code implementation for Python interacting with MongoDB

Python and MongoDB are usually implemented through the pymongo library. pymongo is an official Python driver for interacting with MongoDB databases. Here is a simple example showing how to use pymongo to connect to a MongoDB database and perform some basic database operations (such as inserting, querying, updating, and deleting documents).

Install pymongo

pip install pymongo

Python connection to Mongodb

from pymongo import MongoClient
 
# Create a MongoClient object that is used to connect to the Mongodb database serverclient = MongoClient('mongodb://admin:password@localhost:27017/')

Add data to the database

from mongo_db import client
 
# .insert_one({"name": "Luna"}) 
# .insert_many([{"name":"Lanling King"}, {"name": "Baili Xuance"}]) 
({})

Query data

from mongo_db import client
 
try:
    teachers = ()
    # print(teachers)
    for one in teachers:
        print(one["_id"],one["name"])
 
    # Conditional query    teacher = .find_one({"name":"Lanling King"})
    print(teacher["_id"],teacher["name"])
 
except Exception  as e:
    print(e)

Update and modify data

from mongo_db import client
 
try:
    # Change the entire table. If there is no column in the table, this column will be added.    # .update_many({}, {'$set': {"role":["Class Teacher"]}})    # .update_one({"name": "Luna"},{"$set":{"sex": "Female"}}) 
    # push append (list)    .update_one({"name": "Luna"},{"$push":{"role": "Class Director Wang"}})
 
except Exception as e:
    print(e)

Delete data

from mongo_db import client
 
try:
    # Conditional query    # .delete_one({"name": "Luna"})    # Delete multiple data    .delete_many({})
except Exception as e:
    print(e)

Index

Create indexes to optimize query performance.

collection.create_index([("name", )])

Aggregation framework

Complex data aggregation operations using an aggregation framework

pipeline = [
    {"$match": {"age": {"$gt": 25}}},
    {"$group": {"_id": "$city", "count": {"$sum": 1}}}
]
results = (pipeline)
for result in results:
    print(result)

Affairs

Starting with MongoDB 4.0, it supports multi-document transactions to ensure data consistency and integrity.

with client.start_session() as session:
    with session.start_transaction():
        collection.update_one({"name": "John"}, {"$set": {"age": 32}}, session=session)
        collection.update_one({"name": "Alice"}, {"$set": {"age": 26}}, session=session)
        session.commit_transaction()

Close the connection

()

Things to note

When using pymongo for MongoDB operations, you need to make sure that the MongoDB service has been started and the network connection is normal.

When performing data insertion, update and delete operations, you need to pay attention to the integrity and consistency of the data.

MongoDB's collection is created dynamically, that is, when data is inserted into a non-existent collection, MongoDB will automatically create the collection.

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