In MongoDB you can compare one field to another using $expr:

db.users.find({ $expr: { $eq: ["$created_at", "$updated_at"] } })

Here we get users that their updated_at field is equal to created_at field, here it means that user has not yet updated his profile.

#mongodb #mongo #expr #find

MongoDB server Load Average: 0.5 (It can reach 16)
Database Size: 100GB (It is compressed in MySQL it reaches 300 GB in size!)
Req/Sec: 500

Our server seems hungry for more requests and more data.

#mongodb #mongo #awesomeness

In MongoDB you can use $regex in order to find something based on a regex pattern:

my_col.find({'name': { $regex: '^ali.*' } })

It will find all users that their names start with ali. Now let's say you want to search users based on their phone country code which has a + in its number like +98901.... You need to escape the + character but escape it twice:

my_col.find({'phone': { $regex: '^\\+98.*' } })

#mongoDB #pymongo #regex

Is there a way to create ObjectID from an INT in MongoDB?

import bson

def object_id_from_int(n):
    s = str(n)
    s = '0' * (24 - len(s)) + s
    return bson.ObjectId(s)

def int_from_object_id(obj):
    return int(str(obj))

n = 12345
obj = object_id_from_int(n)
n = int_from_object_id(obj)
print(repr(obj))  # ObjectId('000000000000000000012345')
print(n)  # 12345

#mongodb #objectid #pymongo #python #bson #int

https://medium.com/@xoor/indexing-mongodb-with-elasticsearch-2c428b676343

#mongodb #elastic #elasticsearch #indexing #fulltext #fulltext_search #search #ngram #medium

Did you know you can use jsonSchema in MongoDB to search for documents?

Let's say you have users collection with data below:

{ "_id" : ObjectId("5f64bd1eca8806f2c04fcbe3"), "customer_id" : 100, "username" : "john" }
{ "_id" : ObjectId("5f64bd1eca8806f2c04fcbe5"), "customer_id" : 206, "username" : "new_customer" }
{ "_id" : ObjectId("60420df441558d6671cf54f2"), "customer_id" : "123", "username" : "Ali" }

Now let's say you want to find all documents that has a customer_id of type string instead of int.
In Mongo shell:

let ms = {required: ["customer_id"], properties: {customer_id: {bsonType: "string"}}}

This schema says look for documents that have customer_id field with string type. To search:

> db.customers.find({$jsonSchema: ms})
{ "_id" : ObjectId("60420df441558d6671cf54f2"), "customer_id" : "123", "username" : "Ali" }

Interesting, right? :)

#database #mongodb #jsonSchema #json_schema