MongoDB is a cross-platform, document-oriented database that works on the concept of collections and documents. MongoDB offers high speed, high availability, and high scalability.
Accessing a Collection
1) Getting a list of collection: For getting a list of a MongoDB database’s collections list_collection_names() method is used. This method returns a list of collections.
Syntax:
list_collection_names()
Example:
Sample Database:
Python3
from pymongo import MongoClient # create an client instance of the # MongoDB class mo_c = MongoClient() # create an instance of 'some_database' db = mo_c.GFG # get a list of a MongoDB database's # collections collections = db.list_collection_names() print ("collections:", collections, "\n") |
Output:
collections: ['Geeks']
2) Check if the collection exist or not: To check if the collection attribute exists for the database use hasattr() method. It returns true if the collection is in database otherwise returns false.
Syntax: hasattr(db, ‘collectionname’)
Parameters:
db: It is database object.
collectionname: It is the name of the collection.
Example:
Python3
from pymongo import MongoClient # create an client instance of # the MongoDB class mo_c = MongoClient() # create an instance of 'some_database' db = mo_c.GFG # check collection is exists or not print(hasattr(db, 'Geeks')) |
Output:
True
3) Accessing a Collection: To acces a MongoDB collection name use the below syntax.
Syntax:
database_object.Collectionname or database_object["Collectionname"]
Note: Database_object[“Collectioname”] can be useful in the case where the name of the collection contains a space in between them i.e. in cases like database_object[“Collection name”].
Example:
Python3
from pymongo import MongoClient # create an client instance of # the MongoDB class mo_c = MongoClient() # create an instance of 'some_database' db = mo_c.GFG col1 = db["gfg"] print ("Collection:", col1) |
Output:
Collection: Collection(Database(MongoClient(host=[‘localhost:27017’], document_class=dict, tz_aware=False, connect=True), ‘GFG’), ‘gfg’)
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