flask-sqlalchemy外键错误

Question

我试图在flask-sqlalchemy中的一个表中实现外键，但一直收到这个错误：

    "specify a 'primaryjoin' expression." % self.prop
sqlalchemy.exc.NoForeignKeysError: Could not determine join condition between parent/child tables on rel                 ationship workout_plan_task.user_profiles - there are no foreign keys linking these tables.  Ensure that                  referencing columns are associated with a ForeignKey or ForeignKeyConstraint, or specify a 'primaryjoin                 ' expression.

我有一个“练习”表，还有一个"user_profiles“表。我有两个主键都是"workout_plan_task“表中的外键。

代码如下：

from flask_config import *
from datetime import datetime
from sqlalchemy.orm import relationship

class user_profiles(db.Model):
    __tablename__ = "user_profiles"

    user_ID = db.Column(db.Integer(), primary_key=True, autoincrement=True)
    email_adress = db.Column(db.String())
    age = db.Column(db.Integer())
    sex = db.Column(db.Integer())
    height = db.Column(db.Integer())
    weight = db.Column(db.Integer())
    main_goal = db.Column(db.Integer())
    level_experience = db.Column(db.Integer())
    profile_created_at = db.Column(db.DateTime(), default=datetime.utcnow())


    def __init__(self, email_adress, age, sex, height, weight, main_goal, level_experience, profile_created_at):
        self.email_adress = email_adress
        self.age = age
        self.sex = sex
        self.height = height
        self.weight = weight
        self.main_goal = main_goal
        self.level_experience = level_experience
        self.profile_created_at = profile_created_at

    def __repr__(self):
        return '{}-{}-{}-{}'.format(self.email_adress, self.age, self.sex, self.height, self.weight, self.main_goal, self.level_experience, self.profile_created_at)


class workout_plan_task(db.Model):
    __tablename__ = "workout_plan_task"

    task_ID = db.Column(db.Integer(), primary_key=True)
    user_ID = db.Column(db.Integer, db.ForeignKey('user_ID'), nullable=False, column_hide_backrefs = False)
    workout_plan_ID = db.Column(db.Integer())
    exercise_ID = db.Column(db.Integer, db.ForeignKey('exercise_ID'), nullable=False, column_hide_backrefs = False)
    repetitions = db.Column(db.Integer())
    sets = db.Column(db.Integer())
    pause_time = db.Column(db.Integer())
    day_to_perform_the_task = db.Column(db.String())

    the_user =  relationship("user_profiles", back_populates="workout_plan_task")

    def __init__(self, task_ID, user_ID, workout_plan_ID, exercise_ID, repetitions, sets, pause_time, day_to_perform_the_task):
        self.task_ID = task_ID
        self.user_ID = user_ID
        self.workout_plan_ID = workout_plan_ID
        self.exercise_ID = exercise_ID
        self.repetitions = repetitions
        self.sets = sets
        self.pause_time = pause_time
        self.day_to_perform_the_task = day_to_perform_the_task

    def __repr__(self):
        return '{}-{}-{}-{}-{}-{}-{}-{}'.format(self.task_ID, self.user_ID, self.workout_plan_ID, self.exercise_ID, self.repetitions, self.sets, self.pause_time, self.day_to_perform_the_task)



class exercises(db.Model):
    __tablename__ = "exercises"

    exercise_ID = db.Column(db.Integer(), primary_key=True)
    exercise_name  = db.Column(db.String())
    exercise_type = db.String(db.String())
    muscle_groups_worked_out = db.String(db.String())
    equipment_ID = db.String(db.Integer())



    def __init__(self, exercise_ID, exercise_name, exercise_type, muscle_groups_worked_out, equipment_ID):
        self.exercise_ID = exercise_ID
        self.exercise_name = exercise_name
        self.exercise_type = exercise_type
        self.muscle_groups_worked_out = muscle_groups_worked_out
        self.equipment_ID = equipment_ID

    def __repr__(self):
        return '{}-{}-{}-{}-{}'.format(self.exercise_ID, self.exercise_name, self.exercise_type, self.muscle_groups_worked_out, self.equipment_ID)

有没有人能帮帮我？

Answer 1

在workout_plan_task模型中，您应该将其他表称为user_profiles.user_ID，而不仅仅是user_ID和exercises.exercise_ID，而不仅仅是exercise_ID

因此，更新这些行：

user_ID = db.Column(db.Integer, db.ForeignKey('user_profiles.user_ID'), nullable=False, column_hide_backrefs = False)
exercise_ID = db.Column(db.Integer, db.ForeignKey('exercises.exercise_ID'), nullable=False, column_hide_backrefs = False)