mongodb query return only one field

The blog has moved Https://www.tianmingxing.com MongoDB is an open-source, document-oriented NoSQL (not only SQL) database written using C + +, and one of the most popular NoSQL databases. NoSQL Introduction NoSQL means "Not just SQL", is the

Original link http://www.cnblogs.com/zhangzili/p/4975080.htmlMongoDB knowledge points at a glance1. Start the MongoDB database:Go to the MongoDB installation directory and execute the following commandC:\Program

First, the index introductionIn MongoDB, indexes are used to support efficient queries. If there is no index, MONGODB must scan each document in the entire collection to find a matching document. However, if an appropriate index is established,

In the previous article we talked about MongoDB's CRUD basic operations http://blog.csdn.net/stronglyh/article/details/46812579In this case, let's talk about the advanced--------------of MongoDB.A: Various inquiries1: Conditional operator= This

MongoDB combat Development "0 basic Learning, with complete ASP.Read Catalogue Begin Download MongoDB, and start it Using MongoDB in C # Refactoring (simplifying) code Viewing data using MongoDB's clients Maintaining

This article mainly introduces the PHP operation MongoDB implementation of adding and removing functions, combined with examples of the form of a summary of the PHP operation MongoDB Common skills, and with PHP7 operation MongoDB method, with a

In the four CRUD operations, a record or document is obtained from the collection of mongodb databases. For non-DBAs, query is the most used. Therefore, if you have learned the query, it will be of great help for us to better operate the database in

0) MONGO: Connect MongoDB database via client1) Show DBS---Display the currently created database2) Use test---Create or switch databases3) Db.dropdatabase ()--Delete the current database3) Show Collections: Displays the collection created by the

In the previous article we talked about MongoDB's CRUD basic operations http://blog.csdn.net/stronglyh/article/details/46812579In this case, let's talk about the advanced--------------of MongoDB.A: Various inquiries1: Conditional operator= This

Use MongoDB in Python applications and mongodb in python applications Python is a powerful programming language used in many different types of applications in the development community. Many people know that it is a flexible language that can