TypeError：int（）参数必须是字符串或数字，而不是“模型实例” [英] TypeError: int() argument must be a string or a number, not 'Model Instance'

问题描述

这是我的 models.py ：

from django.db import models

class Location(models.Model):
   location_name = models.CharField(max_length=100)
   def __unicode__(self):
      return self.location_name

class Menu(models.Model):
   location = models.ManyToManyField(Location)
   restaurant_name = models.CharField(max_length=200)
   dish_category = models.CharField(max_length=100)
   dish_name = models.CharField(max_length=200)
   VNV_tag = models.CharField(max_length=100)
   quantity = models.CharField(max_length=10, default='FULL')
   price = models.CharField(max_length=5, default=0)
   def __unicode__(self):
       return self.restaurant_name

我试图使用 xlrd python模块从excel文件填充我的数据库。
这里是我的 populate_db.py 脚本：

I am trying to populate my database from an excel file using xlrd python module. Here's my populate_db.py script:

import os
import xlrd
from menusearch.models import Menu, Location
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'midnitepro.settings')
import django
django.setup()

def populate():
    book = xlrd.open_workbook('/Users/Sahil/Desktop/MNFP1.xlsx')
    sheet = book.sheet_by_index(0)
    count1 = 0
    while count1<sheet.nrows:
        value_list = []
        count2 = 0
        while count2<sheet.ncols:
            value_list.append(sheet.row_values(count1, start_colx=count2, end_colx=count2+1))
            count2 +=1
        add_menuitem(value_list)
        count1 += 1

def add_menuitem(value_list):
    split_query = []
    m = Menu.objects.create()
    value_list = [str(x[0]).encode('utf-8') for x in value_list if x]

    m.restaurant_name = (value_list[0])
    m.dish_category = (value_list[1])
    m.dish_name = (value_list[2])
    m.VNV_tag = (value_list[3])
    m.quantity = (value_list[4])
    m.price = (value_list[5])
    # m.location.add(int(value_list[6]))

    split_query = (value_list[6]).split(",")
    for sq in split_query:
        l = Location.objects.get_or_create(location_name=sq)
        try:
            m.location.add(l)
        except ValueError:
            print "Problem Adding Location to Menu."

    m.save()

if __name__ == '__main__':
    print "Starting population script..."
    from menusearch.models import Menu, Location
    populate()

现在，当我运行populate_db.py脚本时，终端上的输出显示为：向菜单添加位置的问题。我看到populate_db脚本中存在问题： m.location.add（l）
但是这个查询器符合这里给出的语法： https://docs.djangoproject.com/en/1.8/topics/db/examples/many_to_many/

Now when I run the populate_db.py script, the output on the terminal reads: "Problem Adding Location to Menu.". I see that the problem exists here in the populate_db script: m.location.add(l) But this queryset is in line with the syntax given here: https://docs.djangoproject.com/en/1.8/topics/db/examples/many_to_many/

删除try / except之后，我的追溯如下：

After removing the try/except, my traceback reads:

TypeError: int() argument must be a string or a number, not 'Location' 

请说明这里发生了什么。
如何正确地通过查询器向 ManyToManyField 添加一个值。

Please explain what is happening here. And how to properly add a a value to the ManyToManyField via a queryset.

可能的重复： Django错误：TypeError：int（）参数必须是字符串或数字，而不是BuildsTable
但是我会在我使用ManyToManyField的时候，仍然想知道答案。

Possible duplicate: Django Error: TypeError: int() argument must be a string or a number, not 'BuildsTable' But I would still like to know the answer in my case as I'm using a ManyToManyField.

完整追溯：

l= (<Location: Indiranagar>, False)

Inside Loop - sq=  Indiranagar
Traceback (most recent call last):
  File "populate_db.py", line 62, in <module>
populate()
  File "populate_db.py", line 23, in populate
add_menuitem(value_list)
  File "populate_db.py", line 50, in add_menuitem
m.location.add(l)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/fields/related.py", line 973, in add
self._add_items(self.source_field_name, self.target_field_name, *objs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/fields/related.py", line 1079, in _add_items
'%s__in' % target_field_name: new_ids,
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 679, in filter
return self._filter_or_exclude(False, *args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 697, in _filter_or_exclude
clone.query.add_q(Q(*args, **kwargs))
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1304, in add_q
clause, require_inner = self._add_q(where_part, self.used_aliases)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1332, in _add_q
allow_joins=allow_joins, split_subq=split_subq,
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1194, in build_filter
lookups, value)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/fields/related.py", line 1745, in get_lookup_constraint
root_constraint.add(lookup_class(targets[0].get_col(alias, sources[0]), value), AND)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/lookups.py", line 96, in __init__
self.rhs = self.get_prep_lookup()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/lookups.py", line 134, in get_prep_lookup
return self.lhs.output_field.get_prep_lookup(self.lookup_name, self.rhs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 729, in get_prep_lookup
return [self.get_prep_value(v) for v in value]
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 985, in get_prep_value
return int(value)
TypeError: int() argument must be a string or a number, not 'Location'.

推荐答案

要向ManyToManyField添加值，您需要通过传递它们作为参数来添加对象。

To add a value to a ManyToManyField, you need to add the objects by passing them as arguments.

add(obj1, obj2, obj3, ...)

这将把指定的对象添加到相关的对象集。

This will add the specified objects to the related object set.

您可以调用 add（），如下所示：

You can call the add() like below:

menu_object.location.add(loc_obj1, loc_obj2, ...) 

在你的情况下，你需要要做：

l = Location.objects.get_or_create(location_name=sq)[0]

您需要通过索引访问实例 c> 0 as get_or_create 返回一个元组（实例，创建）。然后将这个实例传递给 add（）方法。

You need to access the instance by index 0 as get_or_create returns a tuple (instance, created). Then pass this instance to the add() method.

注意：

使用 add（）多对多关系不会为每个对象调用任何 .save（），而是使用 .bulk_create（）。

Note:
Using add() with a many-to-many relationship will not call any .save() for each object, but rather create the relationships using .bulk_create().

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