如何在 Django/Mysql 中建立一对多关系？

Question

我想了解如何在 Django/Mysql?

中建立一对多关系

这里是models.py（代码如下）

class Flora2Estado(models.Model):
    estado = models.OneToOneField(Estados, models.DO_NOTHING, primary_key=True)
    especie = models.ForeignKey('Listaflor', models.DO_NOTHING)
    class Meta:
        managed = False
        db_table = 'flora2estado'
        unique_together = (('estado', 'especie'),)


class Listaflor(models.Model):
    especie = models.OneToOneField(Flora2Estado, models.DO_NOTHING, primary_key=True)
    familia = models.ForeignKey(Familia, models.DO_NOTHING, blank=True, null=True)
    nome = models.CharField(db_column='especie', max_length=255, blank=True, null=True)  # Field renamed because of name conflict.
    class Meta:
        managed = False
        db_table = 'listaflor'

class Estados(models.Model):
    estado_id = models.AutoField(primary_key=True)
    estado_nome = models.CharField(max_length=100, blank=True, null=True)
    class Meta:
        managed = False
        db_table = 'estados

Answer 1

我认为您想要做的是通过另一个名为 Flora2Estado 的 class 在 Listaflor 和 Estados 之间建立 Many2Many 关系。 Django M2M relation

class Estados(models.Model):
    estado_id = models.AutoField(primary_key=True)
    estado_nome = models.CharField(max_length=100, blank=True, null=True)

    class Meta:
        managed = False
        db_table = 'estados'


class Listaflor(models.Model):
    especie_id = models.AutoField(primary_key=True)
    nome = models.CharField(db_column='especie', max_length=255, blank=True, null=True)
    estados = models.ManyToManyField(Estados, through='Flora2Estado')

    class Meta:
        managed = False
        db_table = 'listaflor'


class Flora2Estado(models.Model):
    estado = models.ForeignKey(Estados, on_delete=models.DO_NOTHING)
    especie = models.ForeignKey(Listaflor, on_delete=models.DO_NOTHING)

    class Meta:
        managed = False
        db_table = 'flora2estado'
        unique_together = (('estado', 'especie'),)

如何在 Django/Mysql 中建立一对多关系？

How to make a one to many relationship in Django/Mysql?

django

foreign-keys

relational-database