SQLAlchemy MySQL 基于SQLAlchemy实现操作MySQL并执行原生sql语句

from sqlalchemy import exists, Column, Integer, String, ForeignKey, DateTime, Text, func
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from conf.parseConfig import parseConf

# 从配置文件中获取数据库信息
host = parseConf.get_conf('MySQLInfo', 'host')
port = parseConf.get_conf('MySQLInfo', 'port')
dbname = parseConf.get_conf('MySQLInfo', 'dbname')
usernm = parseConf.get_conf('MySQLInfo', 'usernm')
passwd = parseConf.get_conf('MySQLInfo', 'passwd')
# 连接数据库
engine_str = "mysql+mysqlconnector://{0}:{1}@{2}:{3}/{4}".format(usernm, passwd, host, port, dbname)
# 创建的数据库引擎
engine = create_engine(engine_str, encoding='utf-8')

#创建session类型
DBSession = sessionmaker(bind=engine)
# 创建session对象，进行增删改查:
session = DBSession()

# 实例化官宣模型 - Base 就是 ORM 模型
Base = declarative_base()


# 创建服务单表 继承Base基类
class ServiceOrder(Base):
  __tablename__ = 'serviceOrderTable'
  serviceOrderId = Column(String(32), primary_key=True, comment='服务单ID')
  serviceDesc = Column(String(512), comment='服务说明')
  transferTimes = Column(String(32), comment='转派次数')
  # 创建更新时间，对数据的更新进行记录
  updateTime = Column(DateTime, server_default=func.now(), onupdate=func.now())


def init_db():
  Base.metadata.create_all(engine)


def drop_db():
  Base.metadata.drop_all(engine)


if __name__ == "__main__":
  # 每次执行时 会判断表的存在性 对于数据库中不存在的表进行创建 已存在的表则可以直接进行增删改查
  init_db()

  ### 首先讲一下使用sqlalchemy执行原生的sql语句###
  # 方式一：
  res = session.execute('select * from ServiceOrder') # res是获取的对象
  all_res_list = res.fetchall() # all_res_list具体的结果 是列表
  print(all_res_list ) # 结果： [('数据提取',), ('非数据提取',)]
  # 方式二：
  conn = engine.connect()
  res = conn.execute('select * from ServiceOrder') 
  all_res_list = res.fetchall()

  ### 使用创建好的session对象进行增删改查 ###
  # 插入单条数据
  # 创建新service0rder对象
  new_serviceorder = ServiceOrder(serviceOrderId='001', serviceDesc='ack', transferTimes='9')
  # 添加到session
  session.add(new_serviceorder)
  # 提交即保存到数据库
  session.commit()

  # 插入多条数据
  serviceorder_list = [ServiceOrder(serviceOrderId='002', serviceDesc='好的', transferTimes='9'),ServiceOrder(serviceOrderId='003', serviceDesc='起床', transferTimes='9')]
  session.add_all(serviceorder_list)
  session.commit()
  # session.close()

  # 查询
  # 查询是否存在 结果是布尔值
  it_exists = session.query(
    exists().where(ServiceOrder.serviceOrderId == '002')
  ).scalar()
  # 创建Query查询，filter是where条件
  # 调用one() first()返回唯一行，如果调用all()则已列表的形式返回所有行:
  server_order = session.query(ServiceOrder).filter(ServiceOrder.serviceOrderId == '003').first()
  print(server_order.serviceDesc)
  serciceorders = session.query(ServiceOrder).filter(ServiceOrder.serviceDesc == '好的').all()

  # 改 更新数据
  # 数据更新，将值为Mack的serviceDesc修改为Danny
  update_obj = session.query(ServiceOrder).filter(ServiceOrder.serviceDesc == 'Mack').update({"serviceDesc": "Danny"})
  # 或则
  update_objp = session.query(ServiceOrder).filter(ServiceOrder.serviceDesc == 'Mack').first()
  update_objp.serviceDesc = 'Danny'
  session.commit()

  # 删除
  update_objk = session.query(ServiceOrder).filter(ServiceOrder.serviceDesc == 'Mack').delete()
  # 或则
  update_objkp = session.query(ServiceOrder).filter(ServiceOrder.serviceDesc == 'Mack').one()
  update_objkp.delete()
  session.commit()
  session.close()