Python MongoDB – bulk_write()

MongoDB 是一个开源的面向文档的数据库。 MongoDB以键值对的形式存储数据，是一个NoSQL数据库程序。 NoSQL 一词的意思是非关系型的。有关 MongoDB 的更详细介绍，请参阅 MongoDB: An Introduction。现在让我们使用Python来了解 MongoDB 中的 Bulk Write 操作。

批量写入（）

PyMongo函数bulk_write()向服务器发送一批写操作。批量执行写入操作会增加写入吞吐量。

Syntax : bulk_write(requests, ordered = True, bypass_document_validation = False, session = None)
Parameters :

• requests : Requests are passed as a list of write operation instances.
• ordered : (Optional) A boolean specifying whether the operation executions are performed in an ordered or unordered manner. By default, it is set to True.
• bypass_document_validation : (Optional) A value indicating whether to bypass document validation.
• session : (Optional) a ClientSession.

示例 1：使用bulk_write()执行多个请求。

# importing the module
from pymongo import MongoClient, InsertOne, DeleteOne, ReplaceOne
  
# creating a MongoClient object 
client = MongoClient() 
     
# connecting with the portnumber and host 
client = MongoClient("mongodb://localhost:27017/") 
   
# accessing the database 
database = client['database']   
   
# access collection of the database 
mycollection = mydatabase['myTable'] 
  
# defining the requests
requests = [InsertOne({"Student name": "Cody"}),
            InsertOne({ "Student name": "Drew"}),
            DeleteOne({"Student name": "Cody"}),
            ReplaceOne({"Student name": "Drew"},
                       { "Student name": "Andrew"}, upsert = True)]
  
# executing the requests
result = mycollection.bulk_write(requests)
  
for doc in mycollection.find({}):
    print(doc)

在这里，前两个文档是使用InsertOne 命令插入的。然后使用DeleteOne命令删除具有Student 名称的文档： Cody 。使用ReplaceOne命令，名称为Drew的学生将替换为名称Andrew。因此，所有这些命令都按顺序执行，我们得到以下输出：

输出 ：

{‘_id’: ObjectId(‘5f060aa5a9666ecd86f5b6bd’), ‘Student name’: ‘Andrew’}

示例 2：

# importing the modules
from pymongo import MongoClient, InsertOne, DeleteOne, ReplaceOne, UpdateOne
  
# creating a MongoClient object 
client = MongoClient() 
     
# connecting with the portnumber and host 
client = MongoClient("mongodb://localhost:27017/") 
   
# accessing the database 
database = client['database']   
   
# access collection of the database 
mycollection = mydatabase['myTable']  
  
# defining the requests
requests = [InsertOne({ "x": 5}),
            InsertOne({ "y": 2}),
            UpdateOne({'x': 5}, {'$inc': {'x': 3}}),
            DeleteOne({ "y": 2})]
  
# executing the requests
result = mycollection.bulk_write(requests)
  
for doc in mycollection.find({}):
    print(doc)

这里首先使用InsertOne命令插入两个文档。然后更新x 值为 5的文档，并将其值增加 3。最后，使用命令DeleteOne删除包含y的文档。

输出 ：

{'_id': ObjectId('5f060cd7358fae75aad1ae94'), 'x': 8}