Django Admin ManyToMany错误(Django Admin ManyToMany error)

 我正在使用内置的django管理站点来保存具有ManyToMany字段的模型的实例。 如果我保存而不是更新管理站点中的模型而没有为ManyToMany字段设置值，则可以保存。 保存模型后，我也可以返回并设置ManyToMany字段。 但是，如果我尝试保存我的模型的新实例，运动，具有ManyToMany字段，Exercise.muscles，设置我得到以下错误： 
 
 
 
 （1452，'无法添加或更新子行：外键约束失败（ vitality projectvitality_exercise_muscles ，CONSTRAINT exercise_id_refs_exercise_id_a5d4ddd6 FOREIGN KEY（ exercise_id ）REFERENCES projectvitality_exercise （ exercise_id ））'） 
 
 
 我的mysql表设置为INNODB。 
 
 我的模型如下： 
 
class Muscle(models.Model):
    def format(self):
            return "name:{0}:".format(self.name)

    def __unicode__(self):
            return unicode(self.name)

    muscle_id = UUIDField(primary_key = True)
    name = models.CharField(max_length=30, blank=False, default="")
    medical = models.CharField(max_length=150, blank=True, default="")
    description = models.TextField(blank=True, default="")

class Exercise(models.Model):
    def format(self):
            return "name:{0}".format(self.name)

    def __unicode__(self):
            return unicode(self.name)

    ISOLATION_TYPE = "isolation"
    COMPOUND_TYPE = "compound"
    FULL_BODY_TYPE = "full"

    EXERCISE_TYPES = (
            (ISOLATION_TYPE, "Isolation"),
            (COMPOUND_TYPE, "Compound"),
            (FULL_BODY_TYPE, "Full Body")
    )

    UPPER_BODY_GROUP = "upper"
    LOWER_BODY_GROUP = "lower"

    GROUP_CHOICES = (
            (UPPER_BODY_GROUP, "Upper Body"),
            (LOWER_BODY_GROUP, "Lower Body")
    )

    exercise_id = UUIDField(primary_key=True)
    name = models.CharField(max_length=30, default="", blank=False)
    description = models.TextField(blank=True, default="")
    group = models.CharField(max_length=255,
            choices=GROUP_CHOICES,
            blank=False,
            default=UPPER_BODY_GROUP)
    exercise_type = models.CharField(max_length=255,
            choices=EXERCISE_TYPES,
            blank=False,
            default=ISOLATION_TYPE)
    muscles = models.ManyToManyField('Muscle', blank=True, null=True)

    class Meta:
            verbose_name = "Exercise"
            verbose_name_plural = "Exercises"

I'm using the the built in django admin site to save instances of a model that has a ManyToMany field. If I save, not update, a model in the admin site without setting a value for the ManyToMany field it saves fine. I can also come back and set the ManyToMany field after saving the model and that works. However, if I try to save a new instance of my model, Exercise, that has the ManyToMany field, Exercise.muscles, set I get the following error:
 
 
 
(1452, 'Cannot add or update a child row: a foreign key constraint fails (vitality.projectvitality_exercise_muscles, CONSTRAINT exercise_id_refs_exercise_id_a5d4ddd6 FOREIGN KEY (exercise_id) REFERENCES projectvitality_exercise (exercise_id))')
 
 
My mysql tables are set to INNODB.
 
My models are as follows:
 
class Muscle(models.Model):
    def format(self):
            return "name:{0}:".format(self.name)

    def __unicode__(self):
            return unicode(self.name)

    muscle_id = UUIDField(primary_key = True)
    name = models.CharField(max_length=30, blank=False, default="")
    medical = models.CharField(max_length=150, blank=True, default="")
    description = models.TextField(blank=True, default="")

class Exercise(models.Model):
    def format(self):
            return "name:{0}".format(self.name)

    def __unicode__(self):
            return unicode(self.name)

    ISOLATION_TYPE = "isolation"
    COMPOUND_TYPE = "compound"
    FULL_BODY_TYPE = "full"

    EXERCISE_TYPES = (
            (ISOLATION_TYPE, "Isolation"),
            (COMPOUND_TYPE, "Compound"),
            (FULL_BODY_TYPE, "Full Body")
    )

    UPPER_BODY_GROUP = "upper"
    LOWER_BODY_GROUP = "lower"

    GROUP_CHOICES = (
            (UPPER_BODY_GROUP, "Upper Body"),
            (LOWER_BODY_GROUP, "Lower Body")
    )

    exercise_id = UUIDField(primary_key=True)
    name = models.CharField(max_length=30, default="", blank=False)
    description = models.TextField(blank=True, default="")
    group = models.CharField(max_length=255,
            choices=GROUP_CHOICES,
            blank=False,
            default=UPPER_BODY_GROUP)
    exercise_type = models.CharField(max_length=255,
            choices=EXERCISE_TYPES,
            blank=False,
            default=ISOLATION_TYPE)
    muscles = models.ManyToManyField('Muscle', blank=True, null=True)

    class Meta:
            verbose_name = "Exercise"
            verbose_name_plural = "Exercises"

原文：https://stackoverflow.com/questions/16887064