SQLAlchemy的主要组件详细讲解

from sqlalchemy import create_engine  
# 创建一个引擎  
engine = create_engine('sqlite:///example.db')  
# 打开一个数据库连接  
with engine.connect() as connection:  
    # 创建一个查询，这里我们查询 "users" 表中的所有数据  
    query = connection.query(users)  
    # 执行查询并打印结果  
    for user in query:  
        print(user)

from sqlalchemy import create_engine, Column, Integer, String, func  
from sqlalchemy.orm import sessionmaker  
from sqlalchemy.ext.declarative import declarative_base  
# 创建ORM对象的基础  
Base = declarative_base()  
# 定义一个User对象  
class User(Base):  
    __tablename__ = 'users'  
    id = Column(Integer, primary_key=True)  
    name = Column(String)  
    age = Column(Integer)  
    gender = Column(String)  
# 创建一个引擎  
engine = create_engine('sqlite:///example.db')  
# 创建Session类  
Session = sessionmaker(bind=engine)  
# 创建一个新的Session对象  
session = Session()  
# 查询所有年龄大于18岁的女性用户  
for user in session.query(User).filter(User.age > 18, User.gender == 'female'):  
    print(user.id, user.name, user.age, user.gender)

from sqlalchemy.sql import table, column  
users = table('users',  
             column('id', Integer),  
             column('name', String),  
             column('age', Integer),  
             column('gender', String),  
             )

from sqlalchemy import create_engine  
engine = create_engine('sqlite:///example.db')  
with engine.connect() as connection:  
    connection.execute(users.create)

from sqlalchemy import create_engine  
from sqlalchemy.orm import sessionmaker  
from sqlalchemy.ext.declarative import declarative_base  
# 创建引擎和会话  
engine = create_engine('sqlite:///example.db')  
Session = sessionmaker(bind=engine)  
session = Session()  
# 查询所有用户信息  
users = session.query(User).all()  
for user in users:  
    print(user.id, user.name, user.age)

from sqlalchemy import create_engine, func  
from sqlalchemy.orm import sessionmaker  
from sqlalchemy.ext.declarative import declarative_base  
# 创建引擎和会话  
engine = create_engine('sqlite:///example.db')  
Session = sessionmaker(bind=engine)  
session = Session()  
# 查询年龄大于18岁的女性用户信息  
female_users = session.query(User).filter(User.gender == 'female', User.age > 18).all()  
for user in female_users:  
    print(user.id, user.name, user.age)