mongodb select columns

Recently MongoDB is frequently shot in the hack news. Many people are more claiming to hate Mongodb,david Mytton on his blog revealing many of the existing problems in MongoDB. But the hated one has the same many preferences, as a comeback: Russell

Production Environment Best Practices1. Linux:1] disable the atime option of the file system/partitionVI/etc/fstabAdd noatime and nodiratime after the corresponding partition itemLabel =/1/ext3 defaults 1 1Label =/data1/Data ext4 defaults, noatime,

MongoDB, as the first database in NoSQL, has been using more and more people in recent years, and as a developer, it is necessary to understand the next MongoDB database. The following will give you the basic knowledge of the MongoDB database, there

In order to save the user data and business data for a site, a database is usually required. MongoDB and node. JS are particularly well-matched because MongoDB is a document-based, non-relational database that is stored in Bson (the lightweight

Configure MongoDB configuration items in the configuration file and back up and restore the database, mongodb backup and recoveryI. mongoDB command line startup option Configuration When mongodb is started using the command line, we can select some

/*** MongoDB $type operator*/ /*** The $type operator is based on the Bson type to retrieve the matching data type in the collection and returns the result.* The types of MongoDB that can be used are shown in the following table:* Type Number Notes*

Install and use mongodb 1. Install and start MongoDB Widndows and linux are basically the same 1. Download the database, Mongodb-linux-x86_64-ubuntu1404-3.0.3.tgz: linux 2. decompress the file and place it in a proper location. Tar-vxf mongodb-linux-

Brief introduction MongoDB is a NoSQL database based on distributed file storage Written by the C + + language, stable and high performance Designed to deliver scalable, high-performance data storage solutions for WEB applications

1.MongoDb IntroductionMongoDB is a distributed storage-based open source database system, also known as a document database, can be stored as a document, data structure has a key-value pair (Key=>value) pair composition, the stored document is

Indexes can often greatly improve the efficiency of queries, and if there is no index, MongoDB must scan every file in the collection and select those records that meet the query criteria when reading the data. This scan full set of query efficiency