Configuration¶

Basic setup can be done by definingMONGODB_SETTINGS onapp.config and creating aMongoEngine instance.

fromflaskimportFlaskfromflask_mongoengineimportMongoEngineapp=Flask(__name__)app.config['MONGODB_SETTINGS']={"db":"myapp",}db=MongoEngine(app)

Mapping Documents¶

To declare a model that represents a Mongo document, create a class thatinherits fromDocument and declare each of the fields.

importmongoengineasmeclassMovie(me.Document):title=me.StringField(required=True)year=me.IntField()rated=me.StringField()director=me.StringField()actors=me.ListField()

If the document has nested fields, useEmbeddedDocument todefined the fields of the embedded document andEmbeddedDocumentField to declare it on the parent document.

classImdb(me.EmbeddedDocument):imdb_id=me.StringField()rating=me.DecimalField()votes=me.IntField()classMovie(me.Document):...imdb=me.EmbeddedDocumentField(Imdb)

Creating Data¶

Instantiate your document class with keyword arguments for the fields.You can also assign values to the field attributes after instantiation.Then calldoc.save().

bttf=Movie(title="Back To The Future",year=1985)bttf.actors=["Michael J. Fox","Christopher Lloyd"]bttf.imdb=Imdb(imdb_id="tt0088763",rating=8.5)bttf.save()

Queries¶

Use the classobjects attribute to make queries. A keyword argumentlooks for an equal value on the field.

bttf=Movies.objects(title="Back To The Future").get_or_404()

Query operators may be used by concatenating them with the field nameusing a double-underscore.objects, and queries returned bycalling it, are iterable.

some_theron_movie=Movie.objects(actors__in=["Charlize Theron"]).first()forrecentsinMovie.objects(year__gte=2017):print(recents.title)

Documentation¶

There are many more ways to define and query documents with MongoEngine.For more information, check out theofficial documentation.

Flask-MongoEngine adds helpful utilities on top of MongoEngine. Checkout theirdocumentation as well.