一對多
- 創(chuàng)建兩個模型
class Person(db.Model):
__tablename__ = 'person'
name = db.Column(db.String(20), primary_key=True)
age = db.Column(db.Integer)
birth = db.Column(db.Date)
phone = db.Column(db.String(11), unique=True)
# 使用關(guān)系函數(shù)定義關(guān)系屬性
cars = db.relationship('Car')
def __repr__(self):
return '姓名：{name} 年齡：{age} 生日：{birth} 電話：{phone}'.format(name=self.name, age=self.age, birth=self.birth,
phone=self.phone)
class Car(db.Model):
name = db.Column(db.String(10), primary_key=True)
price = db.Column(db.Float)
# 定義外鍵(表明.字段名)
course_phone = db.Column(db.String(11), db.ForeignKey('person.phone'))
def __repr__(self):
return '汽車類型：{name} 總價：{price}'.format(name=self.name, price=self.price)
- 通過設(shè)置外鍵建立關(guān)系
@app.cli.command()
def insertpc():
person = Person(name='老趙', age=27, birth=datetime.datetime.now(), phone='17777777777')
car1 = Car(name='五菱宏光', price=55000.00, course_phone='17777777777')
car2 = Car(name='吉利自由艦', price=43000.00, course_phone='17777777777')
db.session.add(person)
db.session.add(car1)
db.session.add(car2)
db.session.commit()
click.echo('insert')
或者通過關(guān)系屬性cars調(diào)用append建立關(guān)系
@app.cli.command()
def insertpc():
person = Person(name='老趙', age=27, birth=datetime.datetime.now(), phone='17777777777')
car1 = Car(name='五菱宏光', price=55000.00)
car2 = Car(name='吉利自由艦', price=43000.00)
db.session.add(person)
person.cars.append(car1)
person.cars.append(car2)
db.session.commit()
click.echo('insert')
通過remove解綁關(guān)系
person.cars.remove(car1)
db.session.commit()
- 查詢
@app.cli.command()
def querypc():
person = Person.query.first()
click.echo(person.cars)
查詢結(jié)果如下：
[汽車類型：五菱宏光 總價：55000.0, 汽車類型：吉利自由艦 總價：43000.0]
建立雙向關(guān)系
- 創(chuàng)建兩個模型
class Person(db.Model):
__tablename__ = 'person'
name = db.Column(db.String(20), primary_key=True)
age = db.Column(db.Integer)
birth = db.Column(db.Date)
phone = db.Column(db.String(11), unique=True)
# 使用關(guān)系函數(shù)定義關(guān)系屬性
cars = db.relationship('Car', back_populates='person')
def __repr__(self):
return '姓名：{name} 年齡：{age} 生日：{birth} 電話：{phone}'.format(name=self.name, age=self.age, birth=self.birth,
phone=self.phone)
class Car(db.Model):
name = db.Column(db.String(10), primary_key=True)
price = db.Column(db.Float)
# 定義外鍵(表明.字段名)
course_phone = db.Column(db.String(11), db.ForeignKey('person.phone'))
person = db.relationship('Person', back_populates='cars')
def __repr__(self):
return '汽車類型：{name} 總價：{price}'.format(name=self.name, price=self.price)
- 建立關(guān)系
@app.cli.command()
def insertpc():
person = Person(name='老趙', age=27, birth=datetime.datetime.now(), phone='17777777777')
car1 = Car(name='五菱宏光', price=55000.00)
car2 = Car(name='吉利自由艦', price=43000.00)
db.session.add(person)
person.cars.append(car1)
person.cars.append(car2)
db.session.commit()
click.echo('insert')
- 查詢
@app.cli.command()
def queryc():
car = Car.query.first()
click.echo('{person} {car} '.format(person=car.person, car=car))
查詢結(jié)果如下：
姓名：老趙 年齡：27 生日：2018-10-24 電話：17777777777 汽車類型：五菱宏光 總價：55000.0
一對一關(guān)系
- 創(chuàng)建兩個模型，注意：創(chuàng)建一對一關(guān)系是通過將
uselist設(shè)為False
class Husband(db.Model):
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
name = db.Column(db.String(10))
age = db.Column(db.Integer)
wife = db.relationship('Wife', uselist=False)
def __repr__(self):
return '老公：{name} 年齡：{age}'.format(name=self.name, age=self.age)
class Wife(db.Model):
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
name = db.Column(db.String(10))
age = db.Column(db.Integer)
husband_id = db.Column(db.Integer, db.ForeignKey('husband.id'))
husband = db.relationship('Husband')
def __repr__(self):
return '老婆：{name} 年齡：{age}'.format(name=self.name, age=self.age)
- 建立關(guān)系，注意：一對一關(guān)系不能使用
append，因為是單個記錄，所以使用=
@app.cli.command()
def inserthw():
husband = Husband(name='老王', age=24)
wife = Wife(name='小紅', age=18)
db.session.add(husband)
husband.wife = wife
db.session.commit()
click.echo('insert')
- 查詢
@app.cli.command()
def queryhw():
husband = Husband.query.first()
click.echo('{husband} {wife}'.format(husband=husband, wife=husband.wife))
查詢結(jié)果如下：
老公：老王 年齡：24 老婆：小紅 年齡：18
多對多關(guān)系
- 建立存儲多對多模型的外鍵對應(yīng)關(guān)系的關(guān)聯(lián)表
association_table = db.Table('association', db.Column('customer_id', db.Integer, db.ForeignKey('customer.id')),
db.Column('product_id', db.Integer, db.ForeignKey('product.id')))
- 建立兩個模型，
secondary設(shè)為關(guān)聯(lián)表的名稱，具體可查看relationship
class Customer(db.Model):
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
name = db.Column(db.String(10))
work = db.Column(db.String(20))
products = db.relationship('Product', secondary=association_table, back_populates='customers')
def __repr__(self):
return '姓名：{name} 公司：{work}'.format(name=self.name, work=self.work)
class Product(db.Model):
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
name = db.Column(db.String(10))
price = db.Column(db.Float)
customers = db.relationship('Customer', secondary=association_table, back_populates='products')
def __repr__(self):
return '產(chǎn)品類型：{name} 單價：{price}'.format(name=self.name, price=self.price)
- 建立關(guān)系
@app.cli.command()
def insertcp():
customer1 = Customer(name='程老板', work='大興有限公司')
customer2 = Customer(name='李老板', work='弘成科技')
customer3 = Customer(name='司馬老板', work='小馬加油有限公司')
product1 = Product(name='絲綢', price=35.12)
product2 = Product(name='鋁合金', price=54.45)
product3 = Product(name='鹽', price=3.00)
db.session.add(customer1)
customer1.products.append(product1)
customer1.products.append(product2)
customer2.products.append(product2)
customer3.products.append(product1)
customer3.products.append(product3)
product1.customers.append(customer1)
product1.customers.append(customer3)
product2.customers.append(customer2)
product2.customers.append(customer1)
product3.customers.append(customer3)
db.session.commit()
click.echo('insert')
- 查詢
@app.cli.command()
def querycp():
customer = Customer.query.first()
click.echo('{customer} 購買了 {products}'.format(customer=customer, products=customer.products))
查詢結(jié)果：
姓名：程老板 公司：大興有限公司 購買了 [產(chǎn)品類型：鋁合金 單價：54.45, 產(chǎn)品類型：絲綢 單價：35.12]
