MongoEngine – Querying Database


MongoEngine – Querying Database



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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

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