插入外国钥匙表中

Question

我是一个sqlalchemy菜鸟，试图通过编写一个小房间可用网络应用程序来学习。我已经将桌子标准化了，所以我有一堆参考表（一周的天数，房间号，课程编号等）和一个带外键的室内时间表表。我最初尝试使用automap函数，但是当它似乎不起作用时，我使用sqlacodegen创建了一个模型，例如：

from sqlalchemy import Column, ForeignKey, Integer, String
from sqlalchemy.orm import relationship
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()
metadata = Base.metadata

class Course(Base):
    __tablename__ = 'courses'
    course_id = Column(Integer, primary_key=True, unique=True)
    course_number = Column(String(8), nullable=False, unique=True)

class DayOfWeek(Base):
    __tablename__ = 'day_of_week'
    day_id = Column(Integer, primary_key=True)
    weekday = Column(String(10), nullable=False)

class EndTime(Base):
    __tablename__ = 'end_time'
    end_id = Column(Integer, primary_key=True, unique=True)
    end_time = Column(String(8), nullable=False)

class Quarter(Base):
    __tablename__ = 'quarter'
    quarter_id = Column(Integer, primary_key=True, unique=True)
    quarter_name = Column(String(10), nullable=False, unique=True)

class Room(Base):
    __tablename__ = 'room'
    room_id = Column(Integer, primary_key=True, unique=True)
    room_number = Column(Integer, nullable=False, unique=True)

class RoomSchedule(Base):
    __tablename__ = 'room_schedule'
    schedule_id = Column(Integer, primary_key=True)
    fk_room_id = Column(ForeignKey('room.room_id'), nullable=False, index=True)
    fk_quarter_id = Column(ForeignKey('quarter.quarter_id'), nullable=False, index=True)
    fk_day_id = Column(ForeignKey('day_of_week.day_id'), nullable=False, index=True)
    fk_start_time = Column(ForeignKey('start_time.time_id'), nullable=False, index=True)
    fk_end_time = Column(ForeignKey('end_time.end_id'), index=True)
    fk_course_id = Column(ForeignKey('courses.course_id'), nullable=False, index=True)
    fk_course = relationship('Course')
    fk_day = relationship('DayOfWeek')
    end_time = relationship('EndTime')
    fk_quarter = relationship('Quarter')
    fk_room = relationship('Room')
    start_time = relationship('StartTime')

class StartTime(Base):
    __tablename__ = 'start_time'
    time_id = Column(Integer, primary_key=True, unique=True)
    start = Column(String(6), nullable=False)

问题是，当我将插入插入室时，它试图将其反向插入到参考表中。我目前插入的尝试看起来像这样：

sched = RoomSchedule()
sched.fk_course = session.query(Course.course_id).filter(Course.course_number =='CS250')
sched.fk_day = session.query(DayOfWeek.day_id).filter(DayOfWeek.weekday =='Tuesday')
sched.fk_end_time = session.query(EndTime.end_id).filter(EndTime.end_time == '22:00')
sched.fk_quarter = session.query(Quarter.quarter_id).filter(Quarter.quarter_name=='1701')
sched.fk_room = session.query(Room.room_id).filter(Room.room_number=='416')
sched.fk_start_time = session.query(StartTime.time_id).filter(StartTime.start=='7:30')
session.add(sched)
session.commit()

我还尝试使用单个类构造函数来提供外国密钥。

如果我想在直python中解决这个问题，我会这样做：

def insert_room_busy(con, room_num, quarter_name, day_name, start_time, end_time, course_number):
    insert_data = 'insert into room_schedule (fk_room_id, fk_quarter_id, fk_day_id, fk_start_time, fk_end_time, fk_course_id) ' 
                  'values( (select room_id from room where room_number= %s), ' 
                  '(select quarter_id from quarter where quarter_name= %s), ' 
                  '(select day_id from day_of_week where weekday= %s), ' 
                  '(select time_id from start_time where start= %s), ' 
                  '(select end_id from end_time where end_time= %s), ' 
                  '(select course_id from courses where course_number= %s));'
    cursor = con.cursor()
    cursor.execute(insert_data, (room_num, quarter_name, day_name, start_time, end_time, course_number))

和笔直的SQL看起来相似，使用子查找来查找外键。

我该如何做"正确"的方式？

Answer 1

我仍然不确定答案，但是我切换到mongodb，现在生活变得更加容易。