Mastering Flask Web Development - Second Edition

Filtering

If you know the exact value of the field you wish to filter by, then you can pass its value as a keyword to the objects method, as follows:

>>> Post.objects(title="Post From The Console").first()
<Post: "Post From The Console">

Unlike SQLAlchemy, we cannot pass truth tests to filter our results. Instead, special keyword arguments are used to test values. For example, to find all posts published after January 1 2015, enter the following:

>>> Post.objects(
        publish_date__gt=datetime.datetime(2015, 1, 1)
).all()
[<Post: "Post From The Console">]

The __gt appended to the end of the keyword is called an operator. MongoEngine supports the following operators:

• ne: Not equal to
• lt: Less than
• lte: Less than or equal to
• gt: Greater than ...