调用数据库函数(SQLAlchemy所写),传入参数查询,二次调用参数为第一次传入参数

问题来源:
封装好远程数据库查询模块
第一次调用,传入参数
第二次调用,传入参数,无效,返回的值仍然时第一次调用的值

问题代码:

createtables文件下代码:

class Design(Base):
    __tablename__='design'
    design_id=Column(Integer,primary_key=True)
    teacher_id = Column(Integer, ForeignKey('teacher.teacher_id'), primary_key=True)
    student_id = Column(Integer, ForeignKey('student.student_id'),primary_key=True)
    name=Column(String(50))

(忘了teacher_id和student_id是主键时错误,还是非主键时错误了)

connect文件下代码:

from sqlalchemy import create_engine, or_
from sqlalchemy.orm import scoped_session, sessionmaker, session
from SQLAlchemy import createtables
import random as r
from SQLAlchemy import choicedemo
#此为远程数据库连接信息
db_connect_string='mysql://账号:密码@ip:3306/数据库名称?charset=utf8'
engine=create_engine(db_connect_string)
SessionType=scoped_session(sessionmaker(bind=engine,expire_on_commit=False))
def GetSession():
    return SessionType()

from contextlib import contextmanager
@contextmanager
def session_scope():
    session=GetSession()
    try:
        yield session
        session.commit()
    except:
        session.rollback()
        raise
    finally:
        session.close()
class Get():
    def Design(self,design_id=None,teacher_id=None, student_id=None, name=None):
        with session_scope() as session:
            return session.query(createtables.Design).filter(
                or_(createtables.Design.design_id == design_id,createtables.Design.teacher_id == teacher_id, createtables.Design.student_id == student_id
                    , createtables.Design.name == name)).first()

当调用design方法的时候就会出现错误。

问题原因:
不详。

解决办法:
定义数据表的时候,将teacher,student主键去除:

class Design(Base):
    __tablename__='design'
    design_id=Column(Integer,primary_key=True)
    teacher_id = Column(Integer, ForeignKey('teacher.teacher_id'))
    student_id = Column(Integer, ForeignKey('student.student_id'))
    name=Column(String(50))

暂时性解决办法。
如果有懂的,希望评论解惑,谢谢

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