处理django-import-export中的foreignKeys导入 [英] Dealing with import of foreignKeys in django-import-export

问题描述

我不明白django-import-export模块如何处理ForeignKeys。
这是一个简单的例子：
models.py

  class TFamilies（models.Model）：
 id_fam = models.AutoField（primary_key = True，unique = True）
 name_fam = models.CharField（max_length = 1024，blank = True，verbose_name ='Famille'）
 
 
 class TGenus（models.Model）：
 id_genus = models.AutoField（primary_key = True，unique = True）
 name_genus = models.CharField（max_length = 1024，verbose_name ='nom de genre' ）
 id_fam = models.ForeignKey（TFamilies，null = True，db_column ='id_fam'，blank = True，verbose_name ='Famille'）
  

我想允许人们添加属与家人相关联的人！一个CSV / XLS只有name_genus和name_fam ...（和id留空）。

大部分时间里，DB已经存在于DB中，Django juste必须找到右侧编号...

admin.py

  class TGenusResource （resource.ModelResource）：
 
 name_fam = fields.Field（widget = widgets.ForeignKeyWidget（TFamilies，'name_fam'））
 
 class Meta：
 model = TGenus 
 import_id_fields = ['id_genus'] 
 
 
 class TGenusAdmin（ImportExportActionModelAdmin）：
 form = TGenusAdminForm 
 resource_class = TGenusResource 
 pass 
  

此配置导致导入界面中的错误：

 行号：1  - 'NoneType'对象没有属性'name_fam'
追溯（最近的最后一次调用）：
文件/ ..... ./lib/python2.7/site-packages/import_export/resources.py，第348行，import_data 
 row_result.object_repr = forc e_text（instance）
文件....... / lib / python2.7 / site-packages / django / utils / encoding.py，第85行，在force_text 
s = six.text_type （s）
 AttributeError：'NoneType'对象没有属性'name_fam'
  

不明白...
我也试过回答： django-import-export资源定义为foreignkey字段？
和类似于：使用django-import-export进行django迁移的外键

我必须使用 before_import 以找到自己比赛？

解决方案

我想，你必须找到自己的比赛！改变tablib数据集中的值是不可能的，所以你必须将条目进行更改，并将它们放回到新行中，然后删除旧的值。

我的excel模板包含列 id_genus （空）， name_genus 和 id_fam 以家庭名称填写！

对于任何降落在这里的人，我发布我的方式：

  def before_import（self，dataset，dry_run）：

在显示给用户
之前对数据集进行标准更正
 
i = 0 
 last = dataset.height  -  1 
 
＃为所有行，搜索给定的家庭ID，并在底部添加一个新行，然后删除第一个
，而i < = last：
＃检查属性是否存在于DB 
 if（TGenus.objects.filter（name_genus = dataset.get_col（2）[0] .capitalize（）））：
 id_genus = TGenus.objects.filter（name_genus = dataset.get_col（2）[0] .capitalize（））[0] .id_genus 
 else：
 id_genus =''
＃检查是否家族存在于DB 
 try：
 TFamilies.objects.get（name_fam = dataset.get_col（2）[0] .capitalize（））
除了TFamilies.DoesNotEx ist：
 raise异常（Family not in DB！）
除了TFamilies.MultipleObjectsReturned：
 pass 
 
＃使用filter而不是get为了防止重复的值，在所有情况下选择第一个
 dataset.rpush（（id_genus，
 dataset.get_col（1）[0]，
 TFamilies.objects.filter（name_fam = dataset .get_col（2）[0] .capitalize（））[0] .id_fam））
 dataset.lpop（）
i = i + 1 
  pre> 
 
 
我的django管理员可以由非sys-admin使用，所以他们可以并复制不在数据库中的属或者家族... 
如果有人有一个想法来处理错误更好，我想读它！ 
此外，我想保留家庭的名字在预览，不仅她的id ...如果你知道如何，我已经发布了另一个问题：是否可以在django import-export中自定义预览模板？  
 
I don't understand how django-import-export module deals with ForeignKeys.
Here is a simple exemple : 
models.py
class TFamilies(models.Model):
    id_fam = models.AutoField(primary_key=True, unique=True)
    name_fam = models.CharField(max_length=1024, blank=True,verbose_name='Famille')


class TGenus(models.Model):
    id_genus = models.AutoField(primary_key=True, unique=True)
    name_genus = models.CharField(max_length=1024,verbose_name='nom de genre')
    id_fam = models.ForeignKey(TFamilies, null=True, db_column='id_fam', blank=True, verbose_name='Famille')
I would like to allow people adding genus with family associated ! A CSV/XLS with only name_genus and name_fam... (and id left blank).

Family already exist in DB most of the time, Django juste have to find the right id number...

admin.py
class TGenusResource(resources.ModelResource):

    name_fam = fields.Field(widget=widgets.ForeignKeyWidget(TFamilies, 'name_fam'))

    class Meta:
        model = TGenus
        import_id_fields = ['id_genus']


class TGenusAdmin(ImportExportActionModelAdmin):
    form = TGenusAdminForm
    resource_class = TGenusResource
    pass
This configuration lead to error in import interface : 
Line number: 1 - 'NoneType' object has no attribute 'name_fam'
Traceback (most recent call last):
File "/....../lib/python2.7/site-packages/import_export/resources.py", line 348, in import_data
row_result.object_repr = force_text(instance)
File "......./lib/python2.7/site-packages/django/utils/encoding.py", line 85, in force_text
s = six.text_type(s)
AttributeError: 'NoneType' object has no attribute 'name_fam'
I don't understand...
I also tried answer there : django-import-export resource definition for foreignkey field?
and sort of like there : Foreign Key in django migration using django-import-export

Do I have to use before_import to find myself the match ? 
解决方案
I figured out that you have to find yourself the match ! It's impossible to alterate values in a tablib dataset so you have to take entries make changes and put them back in a new line then erase the old one. 

My excel template contains columns id_genus (empty), name_genus and id_fam filled by the name of the family ! 

For anyone who landed here I post my way : 
def before_import(self, dataset, dry_run):
        """
        Make standard corrections to the dataset before displaying to user
        """

        i = 0
        last = dataset.height - 1

        # for all lines, search for id of family given and add a new line at the bottom with it then delete the first one
        while i <= last:
            # Check if the Genus exist in DB
            if (TGenus.objects.filter(name_genus=dataset.get_col(2)[0].capitalize())):
                id_genus = TGenus.objects.filter(name_genus=dataset.get_col(2)[0].capitalize())[0].id_genus
            else :
                id_genus = ''
            # Check if the family exists in DB
            try:
                TFamilies.objects.get(name_fam=dataset.get_col(2)[0].capitalize())
            except TFamilies.DoesNotExist:
                raise Exception("Family not in DB !")                   
            except TFamilies.MultipleObjectsReturned:
                pass

            # use of "filter" instead of "get" to prevent duplicate values, select the first one in all cases
            dataset.rpush((id_genus,
                dataset.get_col(1)[0],
                TFamilies.objects.filter(name_fam=dataset.get_col(2)[0].capitalize())[0].id_fam))
            dataset.lpop()
            i = i + 1
My django admin can be used by non sys-admin so, they can and duplicate genus or families that aren't in DB...
If someone have an idea to deal with errors better, I would like to read it ! 
Also, I would like to keep the name of the family in the preview, not only her id... If you know how, I have posted another question about that : Is-it possible to customize the template of preview in django import-export?

                        
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