mongodb sparse index

_ Id Index An index is automatically created for the _ id field for all sets except the set of capacity. This is a special index and cannot be deleted. The _ id index forces that its keywords are unique (except for some scenarios in the partition

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,

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

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

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

Index typeMONGDB indexes are divided into the following types: Single-key index, composite index, geospatial Index, full-text index, and hash indexSingle-key index (single Field Indexes)An index created on a key is a single-key index, which is the

MongoDB data model and index learning summary, mongodb ModelMongoDB data model and index learning Summary 1. MongoDB Data Model: MongoDB data storage structure:MongoDB uses BSON (binary json, binary encoding) data format for document (large files

One, index type (a), one -touch index The index created on one key is the one-touch index, and the single key index is the most common index, such as the _id index created by default by MongoDB. (ii), composite index Indexes built on multiple keys

/*** 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*

MongoDB Data Model and Index learning Summary 1. MongoDB Data Model: MongoDB Data storage structure:MongoDB uses Bson (binary JSON, binary encoded) data format to store and exchange data for documents (large files using the GRIDFS protocol).