It's pretty straightforward if you have an understanding of foreign-keys in the first place.

If you have a user and tweet model, the tweet has a foreign-key to user to indicate the author of the tweet:

class User(Model):
    username = TextField()

class Tweet(Model):
    user = ForeignKeyField(User, backref='tweets')
    content = TextField()

So when you create a tweet, you store the tweet content along with a reference to the user who created it. Thus a tweet has a relationship to one user, and a user has an implicit relationship to any number 0..n tweets.

The backref provides a way to access the tweets that refer to the given user.

user = User.create(username='huey')
Tweet.create(user=user, content='huey-1')
Tweet.create(user=user, content='huey-2')

# Get all tweets by huey.
query = Tweet.select().where(Tweet.user == user)

# Equivalent to above, using backref:
query = user.tweets

It's pretty straightforward if you have an understanding of foreign-keys in the first place.

If you have a user and tweet model, the tweet has a foreign-key to user to indicate the author of the tweet:

class User(Model):
    username = TextField()

class Tweet(Model):
    user = ForeignKeyField(User, backref='tweets')
    content = TextField()

So when you create a tweet, you store the tweet content along with a reference to the user who created it. Thus a tweet has a relationship to one user, and a user has an implicit relationship to any number 0..n tweets.

The backref provides a way to access the tweets that refer to the given user.

user = User.create(username='huey')
Tweet.create(user=user, content='huey-1')
Tweet.create(user=user, content='huey-2')

# Get all tweets by huey.
query = Tweet.select().where(Tweet.user == user)

# Equivalent to above, using backref:
query = user.tweets

Is this feature especially used for NoSQL?

Is this feature especially used for NoSQL?

Is this feature especially used for NoSQL?

sorry,it seems that I've made a mistake.It's my fault...anyway,I just don't understand in your toy code why the object user could be the class variable of Tweet like this:
Tweet.create(user=**user**, content='huey-1')
why not the basic data types like int,char and so on?I haven't met it before,just seems a bit weird for me.

Thank you! This is really useful馃構

what is the default name for backref when we don't specify backref parameter?
<model_name>_set in django for example.

Yes, peewee uses the django convention for the default backref accessor.

Doesn't peewee already know which table to query, since you've established the ForeignKeyField() relationship?

What's the use case for providing some different value for backref?