Django 导入导出 - 唯一约束失败

Question

Django 导入导出 - 唯一约束失败

我正在关注有关如何使用 django-import-export 的文档：

https://django-import-export.readthedocs.io/en/latest/getting_started.html#declaring-fields

我有一个如下所示的 excel 表

我想在这个模型中存储数据：

class ExcelData(models.Model):
    var1 = models.CharField(max_length=200)
    var2 = models.CharField(max_length=200,unique=True)
    var3 = models.CharField(max_length=200)
    var4 = models.CharField(max_length=200)

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这是我走了多远：

@admin.register(ExcelData)
class ViewAdmin(ImportExportModelAdmin):
    exclude = ('id',)

class ExcelDataResource(resources.ModelResource):
    var1 = Field(attribute='var1', column_name='Name')
    var2 = Field(attribute='var2', column_name='SAP_ID')
    var3 = Field(attribute='var3', column_name='Abbreviation')
    var4 = Field(attribute='var4', column_name='Max. Capa')

    class Meta:
        model = ExcelData
        import_id_fields = ('var2',)
        exclude = ('id',)

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这就是我得到的：

这是 CSV 文件：

http://www.sharecsv.com/s/9d1112392cd7f10378de7fc0811dd0c9/REAL_CSV_SIMPLE.csv

当我尝试像这样导入多行时：

我收到此错误：

Line number: 2 - UNIQUE constraint failed: myapp_exceldata.var2
b, e, h, k
Traceback (most recent call last):
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
return Database.Cursor.execute(self, query, params)
sqlite3.IntegrityError: UNIQUE constraint failed: myapp_exceldata.var2

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "D:\Users\...\env\lib\site-packages\import_export\resources.py", line 527, in import_row
self.save_instance(instance, using_transactions, dry_run)
File "D:\Users\...\env\lib\site-packages\import_export\resources.py", line 320, in save_instance
instance.save()
File "D:\Users\...\env\lib\site-packages\django\db\models\base.py", line 746, in save
force_update=force_update, update_fields=update_fields)
File "D:\Users\...\env\lib\site-packages\django\db\models\base.py", line 784, in save_base
force_update, using, update_fields,
File "D:\Users\...\env\lib\site-packages\django\db\models\base.py", line 887, in _save_table
results = self._do_insert(cls._base_manager, using, fields, returning_fields, raw)
File "D:\Users\...\env\lib\site-packages\django\db\models\base.py", line 926, in _do_insert
using=using, raw=raw,
File "D:\Users\...\env\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "D:\Users\...\env\lib\site-packages\django\db\models\query.py", line 1204, in _insert
return query.get_compiler(using=using).execute_sql(returning_fields)
File "D:\Users\...\env\lib\site-packages\django\db\models\sql\compiler.py", line 1384, in execute_sql
cursor.execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 100, in execute
return super().execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 68, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 77, in _execute_with_wrappers
return executor(sql, params, many, context)
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\utils.py", line 90, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: UNIQUE constraint failed: myapp_exceldata.var2

Line number: 3 - UNIQUE constraint failed: myapp_exceldata.var2
c, f, i, l
Traceback (most recent call last):
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
return Database.Cursor.execute(self, query, params)
sqlite3.IntegrityError: UNIQUE constraint failed: myapp_exceldata.var2

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "D:\Users\...\env\lib\site-packages\import_export\resources.py", line 527, in import_row
self.save_instance(instance, using_transactions, dry_run)
File "D:\Users\...\env\lib\site-packages\import_export\resources.py", line 320, in save_instance
instance.save()
File "D:\Users\...\env\lib\site-packages\django\db\models\base.py", line 746, in save
force_update=force_update, update_fields=update_fields)
File "D:\Users\...\env\lib\site-packages\django\db\models\base.py", line 784, in save_base
force_update, using, update_fields,
File "D:\Users\...\env\lib\site-packages\django\db\models\base.py", line 887, in _save_table
results = self._do_insert(cls._base_manager, using, fields, returning_fields, raw)
File "D:\Users\...\env\lib\site-packages\django\db\models\base.py", line 926, in _do_insert
using=using, raw=raw,
File "D:\Users\...\env\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "D:\Users\...\env\lib\site-packages\django\db\models\query.py", line 1204, in _insert
return query.get_compiler(using=using).execute_sql(returning_fields)
File "D:\Users\...\env\lib\site-packages\django\db\models\sql\compiler.py", line 1384, in execute_sql
cursor.execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 100, in execute
return super().execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 68, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 77, in _execute_with_wrappers
return executor(sql, params, many, context)
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\utils.py", line 90, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "D:\Users\...\env\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "D:\Users\...\env\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: UNIQUE constraint failed: myapp_exceldata.var2

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这是 CSV 文件：

http://www.sharecsv.com/s/3f09eb14f7916933604481fd999d03db/REAL_CSV_FULL.csv

谢谢你的任何建议

Answer 1

dir*_*ten 1

导入的工作方式如下：

您需要一个唯一的标识符，以便在导入时导入导出模块“知道”是否需要创建新行或修改现有行。
如果该唯一标识符不是模型的id字段（在您的情况下是自动递增的行号），那么它一定是其他一些唯一字段。您的模型上的所有字段var1都var4没有被声明为唯一，因此您当前已经定义了模型，因此无法导入。
如果字段组合在一起是唯一的，您可以使用多个“id 字段” ，但您的模型也不是这种情况。
导入模块实际上使用作为获取参数来get_or_create()调用您的数据库。unique_id_fields这不应返回超过 1 行，如果返回多行，导入将会崩溃。

为了给您一个想法，并假设SAP_ID是一个唯一标识符（我怀疑Max. Capacity，名称并不表明它是），这应该是您的模型：

class ExcelData(models.Model):
    var1 = models.CharField(max_length=200)
    var2 = models.CharField(max_length=200, unique=True)
    var3 = models.CharField(max_length=200)
    var4 = models.CharField(max_length=200)

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请注意，您的模型还具有隐式字段id，导入导出知道该字段，您必须决定如何处理它，因为它不在您的导入数据中。这就是您收到提到的错误的原因，因为它是模型中的一个字段，您尚未分配给任何内容。最好是排除它，因为它在这里不相关（id如果该行尚不存在，Django 将自动增加一个新行，就像您使用创建模型时一样ExcelData.objects.create()）：

class ExcelDataResource(resources.ModelResource):
    var1 = Field(attribute='var1', column_name='Name')
    var2 = Field(attribute='var2', column_name='SAP_ID')
    var3 = Field(attribute='var3', column_name='Abbreviation')
    var4 = Field(attribute='var4', column_name='Max. Capa')

    class Meta:
        model = ExcelData
        import_id_fields = ('var2',)
        exclude = ('id',)

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使用此代码和以下 csv 文件，它可以工作，我已经测试过它：

class ExcelData(models.Model):
    var1 = models.CharField(max_length=200)
    var2 = models.CharField(max_length=200, unique=True)
    var3 = models.CharField(max_length=200)
    var4 = models.CharField(max_length=200)

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当尝试第二次导入时，或者如果数据库中已经存在一些值为var2d、e 或 f 的数据，您将收到UNIQUE constraint failed的错误exceldata.var2。

注意：如果Max. Capa确实是您的唯一id字段，那么您不应该将其分配给var4而是分配给id。这也行，尽管正如我上面提到的，我怀疑这是你想要的行为。

更新/注释 2 ： django-import-export中存在一个错误，当您尝试更新现有数据时，会导致 UNIQUE 约束异常：如果您的名称与您导入的数据（例如for ）中的名称不同并且您尝试，则会发生这种情况重新导入包含具有相同 id 的现有行的数据（例如，因为您想要更改其他值）。它应该更新该行，但目前它抛出异常。这并不能解释异常（这是因为您也设置为唯一，并且如果您导入具有重复( ) 值的不同行，那么您也会得到异常）。unique_id_fieldcolumn_namevar2SAP_IDvar4var4var4Max. Capa

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