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How to index my collection to use a compound multikey index?
For this, use ensureIndex(). Let us create a collection with documents −
> db.demo678.ensureIndex({id:1,"details.userId":1}); { "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 } > db.demo678.insertOne( ... { ... id:101, ... ... "details" : [ ... { ... "userId" : "1001", ... "userName":"Chris" ... }, ... { ... "userId" : "1002", ... "userName":"David" ... } ... ], ... "otherDetails" : [ ... { ... CountryName:"US", ... EmailId:["Chris@gmail.com","David@gmail.com"] ... } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5ea4276904263e90dac943fc") }
Display all documents from a collection with the help of find() method −
> db.demo678.find();
This will produce the following output −
{ "_id" : ObjectId("5ea4276904263e90dac943fc"), "id" : 101, "details" : [ { "userId" : "1001", "userName" : "Chris" }, { "userId" : "1002", "userName" : "David" } ], "otherDetails" : [ { "CountryName" : "US", "EmailId" : [ "Chris@gmail.com", "David@gmail.com" ] } ] }
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