通过sqlalchemy进行基本的增删改查

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column,Integer,String,DateTime,Boolean
from sqlalchemy.orm import sessionmaker

# 初始化数据库连接:
engine = create_engine('mysql+pymysql://root:123123@localhost/school?charset=utf8',encoding='utf-8')   # school 为数据库名称，为已经存在的
# 创建对象的基类:
Base = declarative_base()

'''   mysql原生语句
CREATE TABLE `news`(
	`id` INT 	NOT NULL AUTO_INCREMENT,
	`title` VARCHAR(200) NOT NULL,
	`content` VARCHAR(2000) NOT NULL,
	`types` VARCHAR(10) NOT NULL,
	`image` VARCHAR(300) NULL,
	`author` VARCHAR(20) NULL,
	`view_count` INT DEFAULT 0,
	`create_at` DATETIME NULL,
	`is_valid` SMALLINT DEFAULT 1,
	PRIMARY KEY(`id`)
)DEFAULT CHARSET 'UTF8';
'''

class News(Base):
    # 表的名字:
    __tablename__ = 'news_alchemy'    # 需要新建的表名字

    # 表的结构:
    id = Column(Integer,primary_key=True)
    title = Column(String(200),nullable=False)
    content = Column(String(2000),nullable=False)
    types = Column(String(10),nullable=False)
    image = Column(String(300),)
    author = Column(String(20),)
    view_count = Column(Integer,)
    create_at = Column(DateTime,)
    is_valid = Column(Boolean,)


# 创建表
#News.metadata.create_all(engine)

# 添加数据
Session_class = sessionmaker(bind=engine)   # 创建与数据库的会话session class ,注意,这里返回给session的是个class,不是实例

class OrmAdd(object):
    def __init__(self):
        self.session = Session_class()  # 生成session实例

    def add(self):
        """插入数据"""
        obj1 = News(
            title = 'D1',
            content = '我是D1',
            types = '链家',
            is_valid = 0,
        )
        obj2 = News(
            title = 'D2',
            content = '我是D2',
            types = '链家',
            is_valid=0,
        )
        obj3 = News(
            title = 'D2',
            content = '我是D2',
            types = '链家',
            is_valid=1,
        )
        self.session.add(obj1)
        self.session.add(obj2)
        self.session.add(obj3)
        self.session.commit()
        return obj1

    def get_one(self):
        """查询一条数据"""
        return self.session.query(News).get(13)

    def get_more(self):
        """查询多条数据"""
        return self.session.query(News).filter_by(is_valid=0)

    def update_one(self,nid):
        """修改一条数据"""
        ud_obj = self.session.query(News).get(nid)
        if ud_obj:
            ud_obj.author = '赵云'
            self.session.add(ud_obj)
            self.session.commit()
            return True
        return False

    def update_more(self,qk):
        """修改多条数据"""
        data_list = self.session.query(News).filter_by(is_valid=qk)
        for ud_obj in data_list:
            ud_obj.author = '小乔'
            self.session.add(ud_obj)
        self.session.commit()

    def del_one(self):
        """删除一条数据"""
        del_obj = self.session.query(News).filter_by(id=15).first()
        if del_obj:
            self.session.delete(del_obj)
            self.session.commit()
            return True
        return False

def main():
    orm = OrmAdd()
    #obj = orm.add()

    # 查询数据
    #obj = orm.get_one()
    obj = orm.get_more()
    if obj:   # 处理查询的数据
        # 获取一条
        # print(obj.types)
        # 获取多条
        for ele in obj:
            print(ele.types)
    else:
        print("查询的对象不存在")

    # 更改数据
    # orm.update_one(110)
    # orm.update_more(False)

    # 删除数据
    orm.del_one()

if __name__ == '__main__':
    main()