วิธีแสดง Index ของ Collection ใน MongoDB

แสดง Index ทั้งหมดของ Collection ด้วย getIndexes()

db.yourCollectionName.getIndexes();

สร้างข้อมูลและ Index ตัวอย่าง

> db.indexDemo.insertOne({"StudentName":"Larry","StudentAge":21});
{ "acknowledged" : true, "insertedId" : ObjectId("5c8f7c4f2f684a30fbdfd599") }
> db.indexDemo.insertOne({"StudentName":"Mike","StudentAge":24});
{ "acknowledged" : true, "insertedId" : ObjectId("5c8f7c552f684a30fbdfd59a") }
> db.indexDemo.insertOne({"StudentName":"Carol","StudentAge":20});
{ "acknowledged" : true, "insertedId" : ObjectId("5c8f7c5e2f684a30fbdfd59b") }

สร้าง Compound Index

> db.indexDemo.createIndex({"StudentName":-1,"StudentAge":-1});

{ "createdCollectionAutomatically" : false, "numIndexesBefore" : 2, "numIndexesAfter" : 3, "ok" : 1 }

แสดง Index ทั้งหมด

> db.indexDemo.getIndexes();

[
  { "v" : 2, "key" : { "_id" : 1 }, "name" : "_id_", "ns" : "test.indexDemo" },
  { "v" : 2, "key" : { "StudentName" : -1 }, "name" : "StudentName_-1", "ns" : "test.indexDemo" },
  { "v" : 2, "key" : { "StudentName" : -1, "StudentAge" : -1 }, "name" : "StudentName_-1_StudentAge_-1", "ns" : "test.indexDemo" }
]

แสดง Index ทั้ง 3 ตัว: _id_ (Default), StudentName_-1 (Single), StudentName_-1_StudentAge_-1 (Compound)