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SQLAlchemyとPostgresを使用してフラスコアプリケーションを作成しています。私はこれでかなり緑色なので、私はフィードバックをいただければ幸いです。しかし、私の直接の質問は、次のモデルのクエリを構築することです。 SQLAlchemyのクエリでは複数の結合を含むSQLAlchemyクエリ
SELECT * FROM items
JOIN prices ON prices.itemId=items.id
WHERE prices.userId = 1 AND prices.available = True
LEFT JOIN (
SELECT * FROM orders WHERE orderDelivery = '2017-07-05') as orders
ON orders.itemId=items.id
：私は、クエリから希望何
from app import db
from sqlalchemy import or_, and_
# Items Table
class Item(db.Model):
__tablename__ = "items"
id = db.Column(db.Integer, primary_key=True)
itemName = db.Column(db.String, unique=True, nullable=False)
measurement = db.Column(db.String, nullable=False)
defaultPrice = db.Column(db.Float, nullable=False)
minimumOrder = db.Column(db.Float, nullable=False)
maximumOrder = db.Column(db.Float, nullable=False)
orders = db.relationship('Order', back_populates='item')
prices = db.relationship('Price', back_populates='item')
def __init__(self, itemName, measurement, defaultPrice,
minimumOrder, maximumOrder):
self.itemName = itemName
self.measurement = measurement
self.defaultPrice = defaultPrice
self.minimumOrder = minimumOrder
self.maximumOrder = maximumOrder
def __repr__(self):
return '<Item {0}>'.format(self.id)
# Users Table
class User(db.Model):
__tablename__ = 'users'
id = db.Column(db.Integer, primary_key=True)
fullName = db.Column(db.String, unique=True, nullable=False)
userName = db.Column(db.String, unique=True, nullable=False)
password = db.Column(db.String, nullable=False)
role = db.Column(db.String, nullable=False)
orders = db.relationship('Order', back_populates='user')
prices = db.relationship('Price', back_populates='user')
def __init__(self, fullName, userName, password, role):
self.fullName = fullName
self.userName = userName
self.password = password
self.role = role
def __repr__(self):
return '<User {0}>'.format(self.userName)
# Availability/Price Table
class Price(db.Model):
__tablename__ = 'prices'
id = db.Column(db.Integer, primary_key=True)
userId = db.Column(db.Integer, db.ForeignKey('users.id'))
user = db.relationship('User', back_populates='prices')
itemId = db.Column(db.Integer, db.ForeignKey('items.id'))
item = db.relationship('Item', back_populates='prices')
available = db.Column(db.Boolean)
priceMeasurement = db.Column(db.String)
price = db.Column(db.Float)
def __init__(self, userId, itemId, priceMeasurement, price):
self.userId = userId
self.itemId = itemId
self.priceMeasurement = priceMeasurement
self.price = price
def __repr__(self):
return '<Price {0}>'.format(self.price)
# Orders Table
class Order(db.Model):
__tablename__ = 'orders'
id = db.Column(db.Integer, primary_key=True)
userId = db.Column(db.Integer, db.ForeignKey('users.id'))
user = db.relationship('User', back_populates='orders')
itemId = db.Column(db.Integer, db.ForeignKey('items.id'))
item = db.relationship('Item', back_populates='orders')
orderQuantity = db.Column(db.Float)
orderMeasurement = db.Column(db.String)
orderPrice = db.Column(db.Float)
orderDelivery = db.Column(db.Date)
orderPlaced = db.Column(db.Date)
def __init__(self, userId, itemId, orderQuantity,
orderMeasurement, orderPrice, orderDelivery, orderPlaced):
self.userId = userId
self.itemId = itemId
self.orderQuantity = orderQuantity
self.orderMeasurement = orderMeasurement
self.orderPrice = orderPrice
self.orderDelivery = orderDelivery
self.orderPlaced = orderPlaced
def __repr__(self):
return '<Order {0}>'.format(self.orderDelivery)
は、次のクエリが返すものと同様のテーブルを返すことです。私はuserIdとorderDelivery変数をルートとセッションからクエリに渡します - @app.route('/user/order/<order_date>') | session['userID']：ログイン時に確立されます。
おかげ
多分[this]（https://stackoverflow.com/questions/27392661/sqlalchemy-left-join-using-subquery）があなたを助けることができます。[this]（https://stackoverflow.com/questions/30311354）/sqlalchemy-joined-with-subquery-issue）を参照してください。 「高度な結合のターゲティングと適応」のトピックの[theicial documentation]（http://docs.sqlalchemy.org/en/latest/orm/query.html）もご確認ください –