在这里,我再次要求你的帮助很少。
我想从用户最喜欢的系列中检索每个系列的一集,这是第一次未观看的(所以下一个要观看)和按上次观看排序的系列。
from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
import logging
from datetime import datetime
from sqlalchemy.ext.associationproxy import association_proxy
app = Flask(__name__)
db = SQLAlchemy(app)
logging.basicConfig()
watched_episodes = db.Table('watched_episodes',
db.Column('user_id', db.Integer, db.ForeignKey('user.id')),
db.Column('episode_id', db.Integer, db.ForeignKey('episode.id'))
)
class User(db.Model):
__tablename__ = 'user'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String)
favorite_series = association_proxy('user_series', 'serie')
watched_episodes = db.relationship('Episode', secondary=watched_episodes,
backref=db.backref('users', lazy='dynamic'))
def __repr__(self):
return '<User {0}>'.format(self.name)
def __init__(self, name):
self.name = name
class UserSerie(db.Model):
__tablename__ = 'user_series'
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), \
primary_key=True)
serie_id = db.Column(db.Integer, db.ForeignKey('serie.id'), \
primary_key=True)
last_watched = db.Column(db.DateTime)
user = db.relationship("User", \
backref=db.backref("user_series", cascade="all, delete-orphan"))
serie = db.relationship("Serie")
def __init__(self, serie=None, user=None, last_watched=None):
self.user = user
self.serie = serie
self.last_watched = datetime.now()
class Serie(db.Model):
__tablename__ = 'serie'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String)
def __init__(self, name):
self.name = name
def __repr__(self):
return '<Serie {0}>'.format(self.name)
class Episode(db.Model):
__tablename__ = 'episode'
id = db.Column(db.Integer, primary_key=True)
air_time = db.Column(db.DateTime)
seas_num = db.Column(db.Integer)
epis_num = db.Column(db.Integer)
serie_id = db.Column(db.Integer, db.ForeignKey('serie.id'))
serie = db.relationship('Serie',
backref=db.backref('episodes', lazy='dynamic'))
def __init__(self, air_time, seas_num, epis_num):
self.air_time = air_time
self.seas_num = seas_num
self.epis_num = epis_num
def __repr__(self):
return '<Episode S{0}E{0}>'.format(self.seas_num, self.epis_num)
u1 = User('user1')
s1 = Serie('Serie1')
s2 = Serie('Serie2')
e1 = Episode(datetime(2008, 05, 30), 1, 1)
e1.serie = s1
e2 = Episode(datetime(2008, 06, 05), 1, 1)
e2.serie = s1
e3 = Episode(datetime(2008, 06, 10), 1, 1)
e3.serie = s1
e4 = Episode(datetime(2012, 01, 01), 1, 1)
e4.serie = s2
e5 = Episode(datetime(2012, 02, 12), 1, 1)
e5.serie = s2
e6 = Episode(datetime(2012, 03, 23), 1, 1)
e6.serie = s2
u1.favorite_series.extend([s1, s2])
db.session.add(u1)
db.session.add(s1)
db.session.add(s2)
db.session.add(e1)
db.session.add(e2)
db.session.add(e3)
db.session.add(e4)
db.session.add(e5)
db.session.add(e6)
db.create_all()
db.session.commit()
logging.getLogger('sqlalchemy.engine').setLevel(logging.INFO)
sub = db.session.query(UserSerie.serie_id, UserSerie.last_watched).\
group_by(UserSerie.serie_id).subquery()
sub2 = db.session.query(Episode).\
filter(Episode.serie_id.in_(x.id for x in u1.favorite_series)).\
order_by(Episode.air_time).\
group_by(Episode.serie_id).subquery()
shows = db.session.query(Serie, sub2).\
outerjoin(sub, Serie.id == sub.c.serie_id).\
outerjoin(sub2).\
filter(Serie.id.in_(\
x.id for x in u1.favorite_series)).\
order_by(sub.c.last_watched)
for s in shows:
print s
虽然这会返回:
(<Serie Serie1>, 3, datetime.datetime(2008, 6, 10, 0, 0), 1, 1, 1)
(<Serie Serie2>, 6, datetime.datetime(2012, 3, 23, 0, 0), 1, 1, 2)
但是我希望Episode像对象一样:
(<Serie Serie1>, <Episode S01E01>)
(<Serie Serie2>, <Episode S01E01>)
提前感谢您的帮助。
答案 0 :(得分:1)
好。似乎没有人能够帮助我。我再次得到朋友Artificial的帮助。
问题通过以下代码解决:
episodes = Episode.query.subquery()
userseries = UserSerie.query.subquery()
# Get the min air time for each of the favorite series.
min_air_times = db.session.query(
Serie.id.label('serie_id'),
db.func.min(episodes.c.id).label('id')
).filter(
Serie.id.in_(x.id for x in u1.favorite_series)
).outerjoin(
userseries,
Serie.id == userseries.c.serie_id
).outerjoin(
episodes,
Serie.id == episodes.c.serie_id
).filter(
~episodes.c.id.in_(x.id for x in u1.watched_episodes)
).filter(
episodes.c.seas_num != 0
).order_by(
desc(userseries.c.last_watched)
).group_by(
Serie.id
).subquery()
# Select the serie and episode.
shows = db.session.query(
Serie,
Episode
).join(
Episode,
Episode.serie_id == Serie.id
).join(
min_air_times,
db.and_(
min_air_times.c.serie_id == Serie.id,
min_air_times.c.id == Episode.id
)
).all()