03 summary of various additions, updates and deletions of mongodb documents

Catalog ： The basic chapter （ Can solve the problem of 80 The problem of ）
01 MongoDB Overview 、 Application scenarios 、 Download mode 、 Connection mode and development history, etc

02 MongoDB data type 、 Key concepts and shell Commonly used instructions

03 MongoDB Various additions to documents 、 to update 、 Delete operation summary

04 MongoDB Various query operations And summary of aggregation operations

05 MongoDB Summarize the various operations of the column

python3 operation MongoDB Various cases of

One . Inserted into the document

Be careful : stay MongoDB in , Inserting content directly will automatically create a collection !

1.1 Use insert() Method

Grammar format : db.COLLECTION_NAME.insert(document)

explain : If the inserted data primary key already exists , You'll throw it org.springframework.dao.DuplicateKeyException abnormal , Prompt for duplicate primary key , Do not save current data .

Case study : Such as directed set user_demo Insert a piece of data in :

db.user_demo.insert({
    "name":"zhangsan", "age": 18})

#  amount to sql Medium 
insert into user_demo(name, age) values("zhangsan", 18);

1.2 Use save() Method （ Obsolete in the new version ）

Grammar format : db.COLLECTION_NAME.save(document)

explain : If _id If the primary key exists, update the data , If it doesn't exist, insert data . The method is obsolete in the new version , have access to db.collection.insertOne() or db.collection.replaceOne() Instead of .

1.3 Use insertOne() Method (3.2 Version added )

Grammar format : db.collection.insertOne()

explain : Inserts a document data into the specified collection , Parameters can be specified ：
writeConcern: Write strategy , The default is 1, That is, it is required to confirm the write operation ,0 Is not required .

Case study : Such as directed set user_demo Insert a piece of data in :

db.user_demo.insertOne({
    "name":"zhangsan", "age": 18})

1.4 insertMany() Method (3.2 Version added )

Grammar format : db.collection.insertMany()

explain : Inserts multiple document data into the specified collection , Parameters can be specified ：
writeConcern: Write strategy , The default is 1, That is, it is required to confirm the write operation ,0 Is not required ;
ordered： Specifies whether to write in order , Default true, Write in order .

Case study : Such as directed set user_demo Insert 2 Data :

db.user_demo.insertMany([{
    "name":"zhangsan", "age": 18}, {
    "name":"lisi", "age": 20}])

Two . Update the document

2.1 Use update() Method

Grammar format :

db.collection.update(
   <query>,
   <update>,
   {
    
     upsert: <boolean>,
     multi: <boolean>,
     writeConcern: <document>
   }
)

explain : Update documents in collection , Parameters can be specified ：

query : update Query criteria for , similar sql update In the query where hinder ;
update : update Object and some updated operators （ Such as $,$inc…） etc. , It can also be understood as sql update In the query set hinder ;
upsert : Optional , This parameter means , If it doesn't exist update The record of , Whether insert objNew,true Insert for , The default is false, Do not insert ;
multi : Optional ,mongodb The default is false, Update only the first record found , If this parameter is zero true, According to the conditions to find out all the records updated ;
writeConcern : Optional , The level at which an exception is thrown .

Case study : Such as directed set user_demo In the name of zhangsan Of users age Update to 21:

db.user_demo.update({
    'name':'zhangsan'},{
    $set:{
    'age': 21}})

#  amount to sql Medium 
update article set age = 21 where name > 'zhangsan';

2.2 Use save() Method

Grammar format :

db.collection.save(
   <document>,
   {
    
     writeConcern: <document>
   }
)

explain : save() Method to replace an existing document with an incoming document ,_id Update the primary key if it exists , Insert if it doesn't exist , Parameters can be specified ：

document : Document data ;
writeConcern : Optional , The level at which an exception is thrown .

Case study : Such as directed set user_demo replace _id by 56064f89ade2f21f36b03136 Document data

db.user_demo.save({
    "_id" :          ObjectId("56064f89ade2f21f36b03136"),
    "name": "wangwu",
    "age": 23})

#  After the update, you can view the results 
db.user_demo.find().pretty()

3.3 MongoDB 3.2 How to add new versions

Update one ：db.collection.updateOne(), Reference resources ：MongoDB Official website -updateOne operation

Update multiple ：db.collection.updateMany(), Reference resources ：MongoDB Official website -updateMany operation

Replace 1 strip ：db.collection.replaceOne(), Reference resources ：MongoDB Official website -replaceOne operation

3、 ... and . Delete the document

Be careful ： Execute... Before deleting the document find() Command to determine if the conditions for execution are correct , This is a good habit .

3.1 Use remove() Method to delete the document

Grammar format : 2.6 After the version

db.collection.remove(
   <query>,
   {
    
     justOne: <boolean>,
     writeConcern: <document>
   }
)

explain : Used to remove data from a collection , Parameter description ：

query :（ Optional ） Conditions for deleted documents .
justOne : （ Optional ） If it is set to true or 1, Only one document is deleted , If this parameter is not set , Or use default values false, Deletes all documents that match the criteria .
writeConcern :（ Optional ） The level at which an exception is thrown .

Case study : For example, in the collection user_demo Remove the name from the middle zhangsan The data of :

db.user_demo.remove({
    "name":"zhangsan"})

db.user_demo.find()  #  Found no named zhangsan The data of the 

#  amount to sql Medium 
delete from user_demo where name = "zhangsan"

Be careful ：remove() Method is out of date , Now the official recommendation is deleteOne() and deleteMany() Method .

3.2 Use deleteOne() Method to delete the document

If you delete user_demo Set below status be equal to D A document of ：

db.inventory.deleteOne({ status: "D"})

3.3 Use deleteMany() Method to delete the document

If you delete user_demo All documents under the collection ：db.user_demo.deleteMany({})

If you delete user_demo Set below status be equal to A All documents of ：db.user_demo.deleteMany({status :"A"})

Four . bulk-write operation

MongoDB Batch operation supports the simultaneous execution of a batch of write operations , Write operations include ： Inserted into the document 、 Update the document 、 Delete the document .

Official website reference ： MongoDB Official website bulk-write operation

bulkWrite The following write operations can be combined freely for batch operations .

• insertOne - Insert a document
• updateOne - Update a document
• updateMany - Update a batch of documents
• replaceOne - Replace a document
• deleteOne - Delete a document
• deleteMany - Delete a batch of documents

Grammar format ：

# operation -  Represents the write operation configuration 
# bulkWrite Receive an array of write operations .
db.collection.bulkWrite(
   [ <operation 1>, <operation 2>, ... ],
)

mongo shell adopt db.collection.bulkWrite() Function to perform batch operations .

Comprehensive case ：

db.inventory.bulkWrite(
      [
         //  Insert a document 
         {
     insertOne :
            {
    
            //  Document content 
               "document" :
               {
    
                  "_id" : 4, "char" : "Dithras", "class" : "barbarian", "lvl" : 4
               }
            }
         },
         {
     insertOne :
            {
    
               "document" :
               {
    
                  "_id" : 5, "char" : "Taeln", "class" : "fighter", "lvl" : 3
               }
            }
         },
         //  Update a document ,updateMany  Updating a batch of documents is similar to 
         {
     updateOne :
            {
    
               //  Update conditions 
               "filter" : {
     "char" : "Eldon" },
               //  Update the content 
               "update" : {
     $set : {
     "status" : "Critical Injury" } }
            }
         },
         //  Delete a document ,deleteMany Deleting multiple documents is similar to 
         {
     deleteOne :
            //  Delete the condition 
            {
     "filter" : {
     "char" : "Brisbane" } }
         },
         //  Replace a document 
         {
     replaceOne :
            {
    
                //  Replacement conditions 
               "filter" : {
     "char" : "Meldane" },
               //  replace content 
               "replacement" : {
     "char" : "Tanys", "class" : "oracle", "lvl" : 4 }
            }
         }
      ]
   );

attach ： Official website crud operation ： Official website crud operation

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