Since MongoDB is a schemaless database, the documents in a collection can have different fields, so an indexed field may not be present in some of them. To create such an index use the sparse option: 1 db.people
MongoDB provides different types of indexes to support specific types of data and queries. Default _id All the collections of MongoDB have an index on the _id field that exists by default. If novaluesspecified for the _id the MongoDB will create an _id field with an ObjectId value. The...
As discussed in a previous post onindexingin MongoDB, we can use the explain() method to learn about the selected query plan. This allows for an examination of the performance of a given query. It can be used in the following manner: db.collection.find().explain() The information generat...
mongodb explain()` # MongoDB Explain() 解析 ## 导言 在使用 MongoDB 进行查询操作时,我们常常需要对查询语句进行优化,以提升查询性能。而 MongoDB 提供了 `explain()` 方法,能够帮助我们深入了解查询的执行计划,从而进行必要的优化。 本文将详细介绍 `explain()` 方法的使用方法和结果解析,帮助读者更好地...
mongodb explain()` # MongoDB Explain() 解析 ## 导言 在使用 MongoDB 进行查询操作时,我们常常需要对查询语句进行优化,以提升查询性能。而 MongoDB 提供了 `explain()` 方法,能够帮助我们深入了解查询的执行计划,从而进行必要的优化。 本文将详细介绍 `explain()` 方法的使用方法和结果解析,帮助读者更好地...