MongoDB Python–插入和替换操作-yiteyi-C++库

先决条件： MongoDB Python基础知识本文主要讨论如何替换集合中的文档或条目。我们只能替换数据库中已经插入的数据。 使用的方法： 替换一个（）和替换多个（）目标：用新文档替换旧文档的全部数据

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MongoDB中的插入

我们首先在MongoDB中插入数据。

                     # Python code to illustrate                   
                     # Insert in MongoDB                   
                     from                               pymongo                               import                               MongoClient                   
                             
                     try                               :                   
                                         conn                               =                               MongoClient()                   
                                         print                               (                               "Connected successfully!!!"                               )                   
                     except                               :                   
                                         print                               (                               "Could not connect to MongoDB"                               )                   
                             
                     # database                   
                     db                               =                               conn.database                   
                             
                     # Created or Switched to collection names: my_gfg_collection                   
                     collection                               =                               db.my_gfg_collection                   
                             
                     emp_rec1                               =                               {                   
                                         "name"                               :                               "Mr.Geek"                               ,                   
                                         "eid"                               :                               24                               ,                   
                                         "location"                               :                               "delhi"                   
                                         }                   
                     emp_rec2                               =                               {                   
                                         "name"                               :                               "Mr.Shaurya"                               ,                   
                                         "eid"                               :                               14                               ,                   
                                         "location"                               :                               "delhi"                   
                                         }                   
                     emp_rec3                               =                               {                   
                                         "name"                               :                               "Mr.Coder"                               ,                   
                                         "eid"                               :                               14                               ,                   
                                         "location"                               :                               "gurugram"                   
                                         }                   
                             
                     # Insert Data                   
                     rec_id1                               =                               collection.insert_one(emp_rec1)                   
                     rec_id2                               =                               collection.insert_one(emp_rec2)                   
                     rec_id3                               =                               collection.insert_one(emp_rec3)                   
                     print                               (                               "Data inserted with record ids"                               ,rec_id1,                               " "                               ,rec_id2,rec_id3)                   
                             
                     # Printing the data inserted                   
                     cursor                               =                               collection.find()                   
                     for                               record                               in                               cursor:                   
                                         print                               (record)                   

输出：

Connected successfully!!!
Data inserted with record ids    
{'_id': ObjectId('5a02227b37b8552becf5ed2a'), 'name': 
'Mr.Geek', 'eid': 24, 'location': 'delhi'}
{'_id': ObjectId('5a02227c37b8552becf5ed2b'), 'name': 
'Mr.Shaurya', 'eid': 14, 'location': 'delhi'}
{'_id': ObjectId('5a02227c37b8552becf5ed2c'), 'name': 
'Mr.Coder', 'eid': 14, 'location': 'gurugram'}

替换_one（）

插入数据后，让我们替换名为Shaurya先生的员工的数据

                     # Python code to illustrate                   
                     # Replace_one() in MongoDB                   
                     from                               pymongo                               import                               MongoClient                   
                             
                     try                               :                   
                                         conn                               =                               MongoClient()                   
                                         print                               (                               "Connected successfully!!!"                               )                   
                     except                               :                   
                                         print                               (                               "Could not connect to MongoDB"                               )                   
                             
                     # database                   
                     db                               =                               conn.database                   
                             
                     # Created or Switched to collection names: my_gfg_collection                   
                     collection                               =                               db.my_gfg_collection                   
                             
                     # replace one of the employee data whose name is Mr.Shaurya                   
                     result                               =                               collection.replace_one(                   
                                         {                               "name"                               :                               "Mr.Shaurya"                               },                   
                                         {                   
                                         "name"                               :                               "Mr.GfG"                               ,                   
                                         "eid"                               :                               45                               ,                   
                                         "location"                               :                               "noida"                   
                             
                                         }                   
                                         )                   
                             
                     print                               (                               "Data replaced with id"                               ,result)                   
                             
                     # Print the new record                   
                     cursor                               =                               collection.find()                   
                     for                               record                               in                               cursor:                   
                                         print                               (record)                   

Connected successfully!!!
Data replaced with id 
{'_id': ObjectId('5a02227b37b8552becf5ed2a'), 'name': 
'Mr.Geek', 'eid': 24, 'location': 'delhi'}
{'_id': ObjectId('5a02227c37b8552becf5ed2b'), 'name': 
'Mr.GfG', 'eid': 45, 'location': 'noida'}
{'_id': ObjectId('5a02227c37b8552becf5ed2c'), 'name': 
'Mr.Coder', 'eid': 14, 'location': 'gurugram'}

我们已成功地替换了员工姓名为“Mr.Shaurya”的文件，并将整个文件替换为新文件，名称为“Mr.GfG”（目前）。

替换许多

考虑到数据与插入的数据相同。 将所有数据项替换为eid:14。

                     # Python code to illustrate                   
                     # Replace_many() in MongoDB                   
                     from                               pymongo                               import                               MongoClient                   
                             
                     try                               :                   
                                         conn                               =                               MongoClient()                   
                                         print                               (                               "Connected successfully!!!"                               )                   
                     except                               :                   
                                         print                               (                               "Could not connect to MongoDB"                               )                   
                             
                     # database                   
                     db                               =                               conn.database                   
                             
                     # Created or Switched to collection names: my_gfg_collection                   
                     collection                               =                               db.my_gfg_collection                   
                             
                     # replace one of the employee data whose name is Mr.Shaurya                   
                     result                               =                               collection.replace_many(                   
                                         {                               "eid"                               :                               14                               },                   
                                         {                   
                                         "name"                               :                               "Mr.GfG"                               ,                   
                                         "eid"                               :                               45                               ,                   
                                         "location"                               :                               "noida"                   
                             
                                         }                   
                                         )                   
                             
                     print                               (                               "Data replaced with id"                               ,result)                   
                             
                     # Print the new record                   
                     cursor                               =                               collection.find()                   
                     for                               record                               in                               cursor:                   
                                         print                               (record)                   

产出应该是：

Connected successfully!!!
Data replaced with id 
{'_id': ObjectId('5a02227b37b8552becf5ed2a'), 'name': 
'Mr.Geek', 'eid': 24, 'location': 'delhi'}
{'_id': ObjectId('5a02227c37b8552becf5ed2b'), 'name': 
'Mr.GfG', 'eid': 45, 'location': 'noida'}
{'_id': ObjectId('5a02227c37b8552becf5ed2c'), 'name': 
'Mr.GfG', 'eid': 45, 'location': 'noida'}

在这里，我们可以看到eid:14的两个条目被新数据替换。（即使数据相同，ObjectId也会不同）。

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