我bulk_create
用来创建模型的对象。每当引发异常时,我该如何处理?
aList = [
Student(name="Jason"),
Student(name="Mark"),
Student(name="Tom"),
Student(name="Jason"),
Student(name="Tom"),
]
Student.objects.bulk_create(aList)
由于模型的字段name
为unique=True
,因此在出现异常时,我必须处理输入。我如何一一处理异常。
这不符合预期,
try:
# bulk_create
except:
# handlers
当引发异常时,该bulk_create
过程终止。
PS。我期待着bulk_create
。或或没有循环create
update_or_create
get_or_create
好吧,那是不可能的。那怎么bulk_create
定义:
def bulk_create(self, objs, batch_size=None):
for parent in self.model._meta.get_parent_list():
if parent._meta.concrete_model is not self.model._meta.concrete_model:
raise ValueError("Can't bulk create a multi-table inherited model")
if not objs:
return objs
self._for_write = True
connection = connections[self.db]
fields = self.model._meta.concrete_fields
objs = list(objs)
self._populate_pk_values(objs)
with transaction.atomic(using=self.db, savepoint=False):
if (connection.features.can_combine_inserts_with_and_without_auto_increment_pk
and self.model._meta.has_auto_field):
self._batched_insert(objs, fields, batch_size)
else:
objs_with_pk, objs_without_pk = partition(lambda o: o.pk is None, objs)
if objs_with_pk:
self._batched_insert(objs_with_pk, fields, batch_size)
if objs_without_pk:
fields = [f for f in fields if not isinstance(f, AutoField)]
self._batched_insert(objs_without_pk, fields, batch_size)
return objs
和_batched_insert
:
def _batched_insert(self, objs, fields, batch_size):
"""
A little helper method for bulk_insert to insert the bulk one batch
at a time. Inserts recursively a batch from the front of the bulk and
then _batched_insert() the remaining objects again.
"""
if not objs:
return
ops = connections[self.db].ops
batch_size = (batch_size or max(ops.bulk_batch_size(fields, objs), 1))
for batch in [objs[i:i + batch_size]
for i in range(0, len(objs), batch_size)]:
self.model._base_manager._insert(batch, fields=fields,
using=self.db)
因此,如您所见bulk_create
,基本上是for
内的循环transaction.atomic
。
还有一件事。在事务块内仅保存一些条目也是不可能的。它要么完全执行,要么根本不执行。
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