MongoDB change, delete a document's Domain property instance
In the development of the site, the initial design may not be reasonable. Or late-business changes can create a somewhat useless property for the document structure. Need to be removed or altered. Because MongoDB is Schema-less, unlike relational databases, column properties are defined in tables rather than records, and each document in a MongoDB collection can have its own domain properties. MongoDB uses db.collections.update to change the domain properties of several documents in the collection, using $set to add fields. $unset Delete the domain.
Delete a field from all documents in the collection
Db.posts.update ({}, {$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 detailed update operation, $unset means to delete the domain
3. The third parameter is an additional option. {Multi:true} means that all documents that meet the requirements are updated, and the first one is only updated by default
can also delete multiple domains at the same time
Db.categories.update ({}, {$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: http://www.lai18.com/content/348300.html, digression: There are a very large number of people are not optimistic about MongoDB, and even listed a lot of MongoDB problems. In fact, MongoDB is just a tool, and what we need is that it can help us to solve the demand, believing MongoDB will be getting better .
Read "MongoDB Technical Knowledge" series of technical Articles to organize the collection
1Basics to get started with MongoDB
2MongoDB Beginner Tutorials (including installation, frequently used commands, related concepts, usage tips, common operations, etc.)
3MongoDB Novice Tutorial of the Shard technology specific explanation
Introduction to the frequently used operations and maintenance technology for 4MongoDB novice Tutorials
5MongoDB Beginner's Tutorial C # driver Operation example
6MongoDB Novice Tutorial of the master-slave replication Configuration specific explanation
Introduction to the aggregation and cursor operation of the 7MongoDB beginner tutorial
8MongoDB Novice Teaching procedures to detail the MongoDB database additions and deletions to check and change the operation
An analysis of the index operation of 9MongoDB Novice Tutorial
10MongoDB Novice 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 changing, deleting a document's Domain attribute instance
MongoDB basic operations in 23Python: connecting, querying instances
24MongoDB Export Query results to file sample
Things to consider 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 permissions
36MongoDB Series Tutorials (eight): Gridfs Storage Specific explanations
Introduction to the features and strengths of 37MongoDB databases
38MongoDB a brief introduction to the five features of MongoDB
39MongoDB Series Tutorial (vi): Java operation MongoDB Instance
40MongoDB Series Tutorial (vii): Specific explanation of MONGODB data structure
41MongoDB Series Tutorial (v): MONGO Grammar and MySQL grammar control learning
42MongoDB Series Tutorial (ii): MongoDB Brief Introduction
43MongoDB Series Tutorial (i): NoSQL origins
A simple introduction to MapReduce in 44MongoDB
45MongoDB Series Tutorial (iii): Download and install MongoDB in Windows
46 on how to back up MongoDB
47MongoDB frequently Used command summary
48MongoDB and MySQL operation control table and difference introduction
49MongoDB Security Configuration Specific explanation
Bson Introduction and usage examples in 50MongoDB
MongoDB change, delete a document's Domain property instance