使用pymongo的bulk_write批量更新不同条件的数据

我们知道可以使用update根据查询条件进行批量更新MongoDB中的数据，但是这种更新的查询条件往往具有单一性，如果我们想一次性提交不同的查询条件进行不同的更新的这个时候update就不能满足了。

多方查找之后发现了 bulk_write 这个函数，下面我们看看如何使用。

>>> for doc in db.test.find({}):
...     print(doc)
...
{u'x': 1, u'_id': ObjectId('54f62e60fba5226811f634ef')}
{u'x': 1, u'_id': ObjectId('54f62e60fba5226811f634f0')}
>>> # DeleteMany, UpdateOne, and UpdateMany are also available.
...

>>> from pymongo import InsertOne, DeleteOne, ReplaceOne
>>> requests = [InsertOne({'y': 1}), DeleteOne({'x': 1}),
...             ReplaceOne({'w': 1}, {'z': 1}, upsert=True)]

>>> result = db.test.bulk_write(requests)
>>> result.inserted_count
1
>>> result.deleted_count
1
>>> result.modified_count
0
>>> result.upserted_ids
{2: ObjectId('54f62ee28891e756a6e1abd5')}
>>> for doc in db.test.find({}):
...     print(doc)
...
{u'x': 1, u'_id': ObjectId('54f62e60fba5226811f634f0')}
{u'y': 1, u'_id': ObjectId('54f62ee2fba5226811f634f1')}
{u'z': 1, u'_id': ObjectId('54f62ee28891e756a6e1abd5')}

我们看到可以一次性提交插入、删除、更新操作，并且可以从返回值中获取到一些新。

我们看下函数源码：

关于参数的注释：

Parameters:
 - `requests`: A list of write operations (see examples above).
 - `ordered` (optional): If ``True`` (the default) requests will be
   performed on the server serially, in the order provided. If an error
   occurs all remaining operations are aborted. If ``False`` requests
   will be performed on the server in arbitrary order, possibly in
   parallel, and all operations will be attempted.
 - `bypass_document_validation`: (optional) If ``True``, allows the
   write to opt-out of document level validation. Default is
   ``False``.
 - `session` (optional): a
   :class:`~pymongo.client_session.ClientSession`.

从源码中我们可以看到bulk_write的返回值是BulkWriteResult对象，我们看下BulkWriteResult对象具有哪些属性：