create index in mongodb

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,

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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

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Previous wordsIndexes 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

MongoDB cluster building (master-slave replication, replica and) (5), mongodb master-slaveVi. Architecture ManagementMongodb master-slave clusters are divided into two types:1: master-Slave replication (master-Slave) -- The Slave server will not

Learning MongoDB 8: MongoDB index (index restrictions) (2), mongodb IndexI. Introduction In the previous article, we introduced basic index operations through db. collection. the createIndex (keys, options) syntax creates an index. We will continue

1.MongoDB Simple Description A MongoDB is an open source database system written in C + + language based on Distributed file storage, which aims to provide scalable and high-performance data storage solutions for Web applications. b MongoDB is a

First, IntroductionIndexing in MongoDB can improve query efficiency, only need to scan the index only a small portion of this collection, and only to load this small part into memory, the efficiency greatly improved, if not indexed, in the query,

Index can improve the performance of the query, if no INDEX,MONGODB must scan the entire collection, starting with the first doc of collection, until the last doc, even if all doc after the first Doc does not meet the query criteria. If there is a