Develop Reference

Unable to update document without specify Primary Key

schema.py:
class Test(Document):
_id = StringField()
classID = StringField(required=True, unique=True)
status = StringField()
====================
database.py:
query = schema.Test(_id = id)
query.update(status = "confirm")
Critical error occured. attempt to update a document not yet saved
I can update the DB only if I specify _id = StringField(primary_key=True), but if I insert a new data, the _id has to be inserted by me instead of automatically created by MongoDB.
Anyone can help me with a solution?
Thanks!

Inserts and updates are distinct operations in MongoDB:
Insert adds a document to the collection
Update finds a document in the collection given a search criteria, then changes this document
If you haven't inserted a document, trying to update it won't do anything since it will never be found by any search criteria. Your ODM is pointing this out to you and prevents you from updating a document you haven't saved. Using the driver you can issue the update anyway but it won't have any effect.
If you want to add a new document to the database, use inserts. To change documents that are already saved, use updates. To change fields on document instances without saving them, consult your ODM documentation to figure out how to do that instead of attempting to save the documents.

python firebase update items using where query

I am using python with firebase, and have a table, I need to update all items that have a specific value in a field, I found out how to query for all the items having that value here and here
Now I need to update all the items that I get in return.
What I would like to do, is to use a single query to perform a single operation that will find the correct items using the where query, and update a certain field to a certain value, I need that functionality in order to keep some data consistent.
Thanks

It is possible to do it, but in more steps:
# the usual preparation
import firebase_admin
from firebase_admin import credentials, firestore
databaseURL = {'databaseURL': "https://<YOUR-DB>.firebaseio.com"}
cred = credentials.Certificate("<YOUR-SERVICE-KEY>.json")
firebase_admin.initialize_app(cred, databaseURL)
database = firestore.client()
col_ref = database.collection('<YOUR-COLLECTION>')
# Query generator for the documents; get all people named Pepe
results = col_ref.where('name', '==', 'Pepe').get()
# Update Pepe to José
field_updates = {"name": "José"}
for item in results:
doc = col_ref.document(item.id)
doc.update(field_updates)
(I use Cloud Firestore, maybe it is different in Realtime Database)

You can iterate through the query and find the DocumentReference in each iteration.
db = firestore.client()
a= request_json['message']['a']
b= request_json['message']['b']
ref = db.collection('doc').where(a'', u'==', u'a').stream()
for i in ref:
i.reference.update({"c":"c"}) # get the document reference and use it to update\delete ...

Firebase python insert

Following the official documentation from firebase i found how to create insite collection a new document with attributes.
doc_ref = db.collection(u'statuses').document()
doc_ref.set({
u'power': -1
})
But on farebase, insite a document, you can put attributes also you can place new collection (as attribute).
My question is how can i add a new collection with my own ID and insite this new collection with new attributes?
I just created an example on firebase to show what i don't know how to add it using python.

This is the answer:
room_a_ref = db.collection(u'rooms').document(u'roomA')
message_ref = room_a_ref.collection(u'messages').document(u'message1')

how to update entire object without changing the id in pymongo?

I am trying to update all properties of the record/object which is stored in MongoDB, now I am trying to do like this.
Deleted the object, but keeping the ID of the object being deleted.
Create a new object with the same ID which I have deleted.
Is it correct ? or What is they to do above objective using pymongo ?
mongo_object = {
_id : 123,
prop_key_1: some_value,
// ... many present
prop_key_n: some_value,
}
def delete(record):
doc = get_db().reviews.delete_many({"id" : record["_id"]})
print(doc.deleted_count)
# all key values are changed, mongo_object is changed except the id.
delete(mongo_object)
db.collection_name.insert_one(mongo_object)
But above code is not deleting the object, the doc.deleted_count is 0.

db.collection_name.update_one({"_id" : record["_id"]}, new_data}
just use update without $set , the document will get replaced completely without changing the _id

from bson.objectid import ObjectId
def replace_one(record):
result = client.test_db.test_collection.replace_one({"_id":ObjectId(record["_id"])}, record,upsert=True)
print(result.matched_count)
What is the correct way to query MongoDB for _id using string by using Python?
Pymongo doc - http://api.mongodb.com/python/current/api/pymongo/collection.html#pymongo.collection.Collection.replace_one

Save List To PyMongo

Never used PyMongo so I'm new to this stuff. I want to be able to save one of my lists to MongoDB. For example, I have a list imageIds = ["zw8SeIUW", "f28BYZ"], which is appended to frequently. After each append, the list imageIds should be saved to the database.
import pymongo
from pymongo import MongoClient
db = client.databaseForImages
and then later
imageIds.append(data)
db.databaseForImages.save(imageIds)
Why doesn't this work? What is the solution?

First, if you don't know what a python dict is, I recommend brushing up on Python fundamentals . Check out Google's Python Class or Learn Python the Hard Way. Otherwise, you will be back here every 10 minutes with a new question...
Now, you have to connect to the mongoDB server/instance:
client = MongoClient('hostname', port_number)
Connect to a database:
db = client.imagedb
Then save the record to the collection "image_data".
record = {'image_ids': imageIds}
db.image_data.save(record)
Using save(), the record dict is updated with an '_id' field which now points to the record in this collection. To update it with a new appended imageIds:
record['image_ids'] = imageIds # Already contains the original _id
db.image_data.save(record)