Create an index to efficiently run complex queries. Let us first create a collection with documents −
> db.demo400.insertOne({SubjectName:"Java Spring"}); { "acknowledged" : true, "insertedId" : ObjectId("5e610720fac4d418a0178572") } > db.demo400.insertOne({SubjectName:"Spring Hibernate"}); { "acknowledged" : true, "insertedId" : ObjectId("5e61072dfac4d418a0178573") } > db.demo400.insertOne({SubjectName:"Java Hibernate"}); { "acknowledged" : true, "insertedId" : ObjectId("5e610736fac4d418a0178574") } > db.demo400.createIndex({SubjectName:"text"}); { "createdCollectionAutomatically" : false, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 }
Display all documents from a collection with the help of find() method −
> db.demo400.find();
This will produce the following output −
{ "_id" : ObjectId("5e610720fac4d418a0178572"), "SubjectName" : "Java Spring" } { "_id" : ObjectId("5e61072dfac4d418a0178573"), "SubjectName" : "Spring Hibernate" } { "_id" : ObjectId("5e610736fac4d418a0178574"), "SubjectName" : "Java Hibernate" }
Following is the query to efficiently perform complex queries on unindexed fields −
> db.demo400.find({ $text: { $search: "Spring" } } )
This will produce the following output −
{ "_id" : ObjectId("5e61072dfac4d418a0178573"), "SubjectName" : "Spring Hibernate" } { "_id" : ObjectId("5e610720fac4d418a0178572"), "SubjectName" : "Java Spring" }