MongoDB Modify, delete a document's Domain property instance

MongoDB Modify, delete a document's Domain property instance

In the development of the website, perhaps the initial design unreasonable, or late business changes, will cause the document structure will have some useless attributes, need to remove or modify, because MongoDB is no Schema, unlike the relational database column properties defined in the table rather than the record, MongoDB Each document in the collection can have its own different domain properties. MongoDB uses db.collections.update to modify the domain properties of several documents in the collection, use $set to increase the domain, $unset delete the domain.
Delete a field for all documents in the collection

Db.posts.update ({}, {$unset: {deleted_at:1}}, {multi:true})

1. The first parameter indicates that some documents are selected, where {} indicates that all documents in the current posts collection are selected

2. The second parameter is a specific update operation, $unset means to delete the domain

3. The third parameter is an additional option, {Multi:true} means that all documents that meet the requirements are updated, and the first one is updated by default

You can also delete multiple domains at the same time

Db.categories.update ({}, {$unset: {deleted_at:1, desc:1}}, {multi:true})

also delete and add domains at the same time

Db.tags.update (    {},    {$unset: {deleted_at:1}, $set: {slug:1, Description:1}},    {multi:true})

This article refers to: http://www.lai18.com/content/348300.html, off-topic: there are a lot of people are not optimistic about MongoDB, and even listed MongoDB many problems, in fact, MongoDB is just a tool, What we need is that it can help us to solve the demand, believing that MongoDB will be getting better.
Read "MongoDB Technical Knowledge" series of technical Articles to organize the collection

1Basics to get started with MongoDB

2MongoDB Getting Started Tutorials (includes installation, common commands, related concepts, tips, common actions, etc.)

3MongoDB Getting Started Tutorial Shard Technology detailed

4MongoDB Introductory tutorials Common operations and Maintenance technology introduction

Example of C # driver operation in 5MongoDB Starter Tutorial

6MongoDB Introductory Tutorial Master-slave replication configuration detailed

Introduction to the aggregation and cursor operations of the 7MongoDB Getting Started tutorial

8MongoDB Getting Started teaching the operation of adding and deleting MongoDB database

An analysis of index operation of 9MongoDB Getting Started tutorial

10MongoDB Getting Started tutorial of the MongoDB database installation diagram under Windows

11MongoDB query field does not create an index caused by Connection Timeout exception solution case sharing

12MongoDB log file is too large a workaround

13MongoDB Community Edition and Enterprise Edition difference comparison table

14MongoDB Chinese Community Initiator takes you to learn MongoDB.

Analysis on performance bottleneck of 15 MongoDB database

The method and performance of 16MongoDB paging query

Cluster architecture implementation of 17MongoDB Shard storage

18Mongodb Bulk deletion of Gridfs file instances

19Mongodb adding, removing Shard server instances

20Mongodb adding, removing Arbiter node instances

MongoDB Installation and configuration tutorial under 21CentOS system

22MongoDB Modifying and deleting a document's Domain property instance

MongoDB basic operations in 23Python: connecting, querying instances

24MongoDB Export Query Results to file example

Things to keep in mind when creating indexes in 25MongoDB

Some pits in 26MongoDB (best not to use)

27 adding user rights to MongoDB sharing method

Simple installation and basic operation of MongoDB under 28Linux system

Basic management commands for the 29MongoDB tutorial

Aggregation of 30MongoDB Tutorials (count, distinct, and group)

Introduction to the index of 31MongoDB tutorials

Data manipulation examples of 32MongoDB tutorials

Basics of getting Started with 33MongoDB tutorials

Examples of query operations for 34MongoDB tutorials

35MongoDB Series Tutorial (iv): Set User access rights

36MongoDB Series Tutorial (eight): Gridfs storage

Introduction to features and advantages of 37MongoDB database

38MongoDB about MongoDB Five features

39MongoDB Series Tutorial (vi): Java operation MongoDB Instance

40MongoDB Series Tutorial (vii): A detailed description of the MONGODB data structure

41MongoDB Series Tutorial (v): MONGO Grammar and MySQL syntax comparison learning

42MongoDB Series Tutorial (ii): About MongoDB

43MongoDB Series Tutorial (i): NoSQL origins

Introduction to MapReduce in 44MongoDB

45MongoDB Series Tutorial (iii): Download and install MongoDB in Windows

46 on how to back up MongoDB

47MongoDB Common Command Summary

48MongoDB and MySQL operation comparison table and the difference introduction

49MongoDB Security Configuration Detailed

Bson Introduction and usage examples in 50MongoDB

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MongoDB Modify, delete a document's Domain property instance