MongoEngine - Querying Database

The connect() function returns a MongoClient object. Using list_database_names() method available to this object, we can retrieve number of databases on the server.

from mongoengine import *
con=connect('newdb')
dbs=con.list_database_names()
for db in dbs:
print (db)

It is also possible to obtain list of collections in a database, using list_collection_names() method.

collections=con['newdb'].list_collection_names()
for collection in collections:
   print (collection)

As mentioned earlier, the Document class has objects attribute that enable access to objects associated with the database.

The newdb database has a products collection corresponding to Document class below. To get all documents, we use objects attribute as follows −

from mongoengine import *
con=connect('newdb')
class products (Document):
ProductID=IntField(required=True)
Name=StringField()
price=IntField()
for product in products.objects:
print ('ID:',product.ProductID, 'Name:',product.Name, 'Price:',product.price)

Output

ID: 1 Name: Laptop Price: 25000
ID: 2 Name: TV Price: 50000
ID: 3 Name: Router Price: 2000
ID: 4 Name: Scanner Price: 5000
ID: 5 Name: Printer Price: 12500