为此,请使用ensureIndex()
。让我们创建一个包含文档的集合-
> 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") }
在find()
方法的帮助下显示集合中的所有文档-
> db.demo678.find();
这将产生以下输出-
{ "_id" : ObjectId("5ea4276904263e90dac943fc"), "id" : 101, "details" : [ { "userId" : "1001", "userName" : "Chris" }, { "userId" : "1002", "userName" : "David" } ], "otherDetails" : [ { "CountryName" : "US", "EmailId" : [ "Chris@gmail.com", "David@gmail.com" ] } ] }