SQLAlchemy高级ORM之改查删除及GROUP,JOIN...

按书上案例来的。

#coding=utf-8

from datetime import datetime
from sqlalchemy import (MetaData, Table, Column, Integer, Numeric, String, Boolean,
                        DateTime, ForeignKey, create_engine, CheckConstraint)
from sqlalchemy import (insert, select, update, delete, text, desc, cast, and_, or_, not_)
from sqlalchemy import (Table, ForeignKeyConstraint)
from sqlalchemy.sql import (func, cast, )
from sqlalchemy.exc import IntegrityError
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import (relationship, backref, sessionmaker)

Base = declarative_base()

class Cookie(Base):
    __tablename__ = 'cookies'

    cookie_id = Column(Integer(), primary_key=True)
    cookie_name = Column(String(50), index=True)
    cookie_recipe_url = Column(String(255))
    cookie_sku = Column(String(55))
    quantity = Column(Integer())
    unit_cost = Column(Numeric(12, 2))

    def __repr__(self):
        return "Cookie(cookie_name='{self.cookie_name}', " \
               "cookie_recipe_url='{self.cookie_recipe_url}', " \
               "cookie_sku='{self.cookie_sku}', " \
               "quantity={self.quantity}, " \
               "unit_cost={self.unit_cost})".format(self=self)

class User(Base):
    __tablename__ = 'users'

    user_id = Column(Integer(), primary_key=True)
    username = Column(String(15), nullable=False, unique=True)
    email_address = Column(String(255), nullable=False)
    phone = Column(String(20), nullable=False)
    password = Column(String(25), nullable=False)
    created_on = Column(DateTime(), default=datetime.now)
    updated_on = Column(DateTime(), default=datetime.now, onupdate=datetime.now)

    def __repr__(self):
        return "User(username='{self.username}', " \
               "email_address='{self.email_address}', " \
               "phone='{self.phone}', " \
               "password='{self.password}')".format(self=self)

class Order(Base):
    __tablename__ = 'orders'

    order_id = Column(Integer(), primary_key=True)
    user_id = Column(Integer(), ForeignKey('users.user_id'))
    shipped = Column(Boolean(), default=False)

    user = relationship("User", backref=backref('orders', order_by=order_id))

    def __repr__(self):
        return "Order(user_id={self.user_id}, " \
               "shipped={self.shipped})".format(self=self)

class LineItem(Base):
    __tablename__ = 'line_items'

    line_item_id = Column(Integer(), primary_key=True)
    order_id = Column(Integer(), ForeignKey('orders.order_id'))
    cookie_id = Column(Integer(), ForeignKey('cookies.cookie_id'))
    quantity = Column(Integer())
    extended_cost = Column(Numeric(12, 2))

    order = relationship("Order", backref=backref('line_items', order_by=line_item_id))
    cookie = relationship("Cookie", uselist=False)

    def __repr__(self):
        return "LineItems(order_id={self.order_id}, " \
               "cookie_id={self.cookie_id}, " \
               "quantity={self.quantity}, " \
               "extended_cost={self.extended_cost})".format(self=self)

class Employee(Base):
    __tablename__ = 'employees'

    id = Column(Integer(), primary_key=True)
    manager_id = Column(Integer(), ForeignKey('employees.id'))
    name = Column(String(255), nullable=False)

    manager = relationship("Employee", backref=backref('reports'), remote_side=[id])

engine = create_engine('mysql+pymysql://xxx')
Base.metadata.create_all(engine)

Session = sessionmaker(bind=engine)
session = Session()
'''
query = session.query(Cookie)
cc_cookie = query.filter(Cookie.cookie_name == "chocolate chip").first()
cc_cookie.quantity = cc_cookie.quantity + 120
session.commit()
print(cc_cookie.quantity)

query = session.query(Cookie)
query = query.filter(Cookie.cookie_name == "chocolate chip")
query.update({Cookie.quantity: Cookie.quantity - 20})
cc_cookie = query.first()
print(cc_cookie.quantity)

query = session.query(Cookie)
query = query.filter(Cookie.cookie_name == "oatmeal raisin")
dcc_cookie = query.one()
session.delete(dcc_cookie)
session.commit()
dcc_cookie = query.first()
print(dcc_cookie)

query = session.query(Cookie)
query = query.filter(Cookie.cookie_name == "peanut butter")
query.delete()
pea_cookie = query.first()
print(pea_cookie)

cookiemon = session.query(User).filter(User.username=="cookiemon").one()
cakeeater = session.query(User).filter(User.username=="cakeeater").one()
pieperson = session.query(User).filter(User.username=="pieperson").one()

o1 = Order()
o1.user = cookiemon
session.add(o1)

cc = session.query(Cookie).filter(Cookie.cookie_name=="chocolate chip").first()
line1 = LineItem(cookie=cc, quantity=2, extended_cost=1.00)
pb = session.query(Cookie).filter(Cookie.cookie_name=="molasses").first()
line2 = LineItem(quantity=12, extended_cost=3.00)
line2.cookie = pb
line2.order = o1

o1.line_items.append(line1)
o1.line_items.append(line2)
session.commit()

o2 = Order()
o2.user = cakeeater
cc = session.query(Cookie).filter(Cookie.cookie_name =="chocolate chip").first()
line1 = LineItem(cookie=cc, quantity=24, extended_cost=12.00)
oat = session.query(Cookie).filter(Cookie.cookie_name =="dark chocolate chip").first()
line2 = LineItem(cookie=oat, quantity=6, extended_cost=6.00)
o2.line_items.append(line1)
o2.line_items.append(line2)
session.add(o2)
session.commit()

query = session.query(Order.order_id, User.username, User.phone,
                      Cookie.cookie_name, LineItem.quantity,
                      LineItem.extended_cost)
query = query.join(User).join(LineItem).join(Cookie)
results = query.filter(User.username=='cookiemon').all()
print(results)

query = session.query(User.username, func.count(Order.order_id))
query = query.outerjoin(Order).group_by(User.username)
for row in query:
    print(row)

marsha = Employee(name='Marsha')
fred = Employee(name='Fred')

marsha.reports.append(fred)

session.add(marsha)
session.commit()

for report in marsha.reports:
    print(report.name)

query = session.query(User.username, func.count(Order.order_id))
query = query.outerjoin(Order).group_by(User.username)
for row in query:
    print(row)

def get_orders_by_customer(cust_name, shipped=None, details=False):
    query = session.query(Order.order_id, User.username, User.phone)
    query = query.join(User)
    if details:
        query = query.add_columns(Cookie.cookie_name, LineItem.quantity,
                                  LineItem.extended_cost)
        query = query.join(LineItem).join(Cookie)
    if shipped is not None:
        pass
        # query = query.where(Order.shipped == shipped)
    results = query.filter(User.username == cust_name).all()
    return results

print get_orders_by_customer('cakeeater')
print get_orders_by_customer('cakeeater', details=True)
print get_orders_by_customer('cakeeater', shipped=True)
print get_orders_by_customer('cakeeater', shipped=False)
print get_orders_by_customer('cakeeater', shipped=False, details=True)

query = session.query(User).filter(text("username='cookiemon'"))
print(query.all())
'''