why create index in mongodb - Wikitechy https://www.wikitechy.com/interview-questions/tag/why-create-index-in-mongodb/ Interview Questions Mon, 04 Apr 2022 05:50:34 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png why create index in mongodb - Wikitechy https://www.wikitechy.com/interview-questions/tag/why-create-index-in-mongodb/ 32 32 What is the use of Index in Mongodb ? https://www.wikitechy.com/interview-questions/mongodb/what-is-the-use-of-index-in-mongodb/ https://www.wikitechy.com/interview-questions/mongodb/what-is-the-use-of-index-in-mongodb/#respond Mon, 04 Apr 2022 05:50:34 +0000 https://www.wikitechy.com/interview-questions/?p=4068
  • MongoDB is one of the leading NoSQL database. It is written in C++ Program.
  • It provides high performance and availability and high scalable.
  • Indexing in MongoDB is used to make query processing more efficient.
  • The MongoDB scan every document in the collection and retrieve only those documents that match the query, where there is no indexing.
  • Indexes are special data structures that stores some information related to the documents such that it becomes easy for MongoDB to find the right data file.
  • Indexes are ordered by the value of the field specified in the index.
    • Index Creating :
    •  createIndex() is a method that allows user to create an index.
    Syntax :

    For Example,

    db.mycol.createIndex({“age”:1})
    {
    “createdCollectionAutomatically” : false,
    “numIndexesBefore” : 1,
    “numIndexesAfter” : 2,
    “ok” : 1
    }
    • In createIndex() method, there are five types of parameters:
      1. background (Boolean)
      2. unique (Boolean)
      3. name (string)
      4. sparse (Boolean)
    Index for Drop :
    • dropIndex() is a method that allows users to drop an index.
    • This method can delete only one index at a time.
    • MongoDB provides the dropIndexes() method that takes multiple indexes as its parameters.
    Syntax :

    Get description of all indexes :
    • It will retrieve all the description of the indexes created within the collection.
    Syntax :

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