Question

在这里，我正在努力处理异常，这里是我的数据模型的详细信息。

路线模型 -

class Routes(models.Model):
    serial_no = models.IntegerField(primary_key=True)
    toll = models.CharField(max_length=1000, blank=True, null=True)
    cost = models.CharField(max_length=300, blank=True, null=True)
    t = models.ForeignKey('Tollmaster', models.DO_NOTHING, blank=True, null=True)
    r = models.ForeignKey(Routeinfo, models.DO_NOTHING)

    class Meta:
        managed = True
        db_table = 'routes'
        unique_together = (('serial_no', 'r'),)

但在管理员面板中我收到错误

MultipleObjectsReturned at /admin/tollm/routes/27/change/
get() returned more than one Routes -- it returned 2!
Request Method: GET
Request URL:    http://127.0.0.1:8000/admin/tollm/routes/27/change/
Django Version: 1.11.5
Exception Type: MultipleObjectsReturned
Exception Value:    
get() returned more than one Routes -- it returned 2!
Exception Location: C:\Users\prash\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\query.py in get, line 384
Python Executable:  C:\Users\prash\AppData\Local\Programs\Python\Python36-32\python.exe
Python Version: 3.6.2

我正在使用Postgresql数据库，这是此表的架构，

              Table "public.routes"
  Column   |          Type           | Modifiers
-----------+-------------------------+-----------
 serial_no | integer                 | not null
 toll      | character varying(1000) |
 cost      | character varying(300)  |
 t_id      | integer                 |
 r_id      | character varying(300)  | not null
Indexes:
    "sno_rid_pkey" PRIMARY KEY, btree (serial_no, r_id)
Foreign-key constraints:
    "r_rinfo_fk" FOREIGN KEY (r_id) REFERENCES routeinfo(r_id)
    "t_id_fk" FOREIGN KEY (t_id) REFERENCES tollmaster1(tid)

任何帮助将不胜感激。

Answer 1

您的模型与表架构不匹配。表模式在serial_no和r_id上有一个多列主键，而您的模型将serial_no指定为单列主键。

Django不支持多列主键see here for the details

我建议您更改架构以添加单独的自动递增主键列“id”，并将当前主键更改为唯一约束

如何处理Django - 异常类型：MultipleObjectsReturned

1 个答案: