first experiment with pymongo python client commands

mongo_commands.py

#pip install pymongo -> to install pymongo
from pymongo import MongoClient
import pprint

#creating client, database, collection and inserting one record
client = MongoClient()
print(client.list_database_names()) #will not be printed here
db = client['python_test_db']
collection = db['actors']
actor = {
  name: 'Robert Downey Jr'
}
data = collection.insert_one(actor)
data_id = data.inserted_id
print(data_id)
print(db.list_collection_names())
print(client.list_database_names()) #will be printed here

#querying
print(db.actors.find_one())
pprint.pprint(db.actors.find_one()) #this doesn't work if customised id is used or if the number of attributes is less than two
pprint.pprint(db.actors.find_one({"_id":'60993d7c42cddfa5e66bfd2d'})) #this doesn't work, returns None
pprint.pprint(db.actors.find_one({"_id":data_id})) #this works

#find returns pymongo cursor
for d in db.actors.find().sort('name'):
  pprint.pprint(d)
#or
for d in collection.find().sort('name'):
  pprint.pprint(d)

#filtering
db.actors.count_documents({"name":"Robert Downey Jr"})

#updating
db.actors.update_many({"name": {"$regex": "^Robert"}}, {"$set": {"name": "Steve Rogers"}})
#or
collection.update_many({"name": {"$regex": "^Robert"}}, {"$set": {"name": "Steve Rogers"}})

#limit
for d in db.actors.find().limit(1):
  pprint.pprint(d)
  
#delete
db.actors.delete_one({"name": "Steve Rogers"})
#or
collection.delete_one({"name": "Steve Rogers"})
  
#insertion
db = client.agg
collection = db.grades
docs = [
    {'s_id': 1,'c_id': 1,'grades': 10},
    {'s_id': 1,'c_id': 2,'grades': 15},
    {'s_id': 1,'c_id': 3,'grades': 50},
    {'s_id': 2,'c_id': 1,'grades': 40},
    {'s_id': 2,'c_id': 2,'grades': 20},
    {'s_id': 2,'c_id': 3,'grades': 11},
    {'s_id': 3,'c_id': 1,'grades': 16},
    {'s_id': 3,'c_id': 2,'grades': 18},
    {'s_id': 3,'c_id': 3,'grades': 37},
    {'s_id': 4,'c_id': 1,'grades': 23},
    {'s_id': 4,'c_id': 2,'grades': 41},
    {'s_id': 4,'c_id': 3,'grades': 53}
]
db.grades.insert_many(docs)

#aggregation
for doc in db.grades.aggregate([{"$group":{"_id":"$s_id","total":{"$sum":"$grades"}}},{"$sort":{"_id":pymongo.ASCENDING}},{"$limit":2}]):
    pprint.pprint(doc)
    print()