是的,您可以使用聚合框架来实现。首先让我们创建一个包含文档的集合-
> db.sliceOfSliceDemo.insertOne( ... { ... "Name": "John", ... "Details": [["First 1:1", "First 1:2"],["second 2:1","Second 2:2"]] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5ccf3fcfdceb9a92e6aa195a") }
以下是在find()
方法的帮助下显示集合中所有文档的查询-
> db.sliceOfSliceDemo.find().pretty();
这将产生以下输出-
{ "_id" : ObjectId("5ccf3fcfdceb9a92e6aa195a"), "Name" : "John", "Details" : [ [ "First 1:1", "First 1:2" ], [ "second 2:1", "Second 2:2" ] ] }
以下是获取切片的查询,即在MongoDB中实现切片链-
> db.sliceOfSliceDemo.aggregate([ {$match:{"Name":"John"}}, {$unwind:"$Details"}, {$unwind:"$Details"}, {$group:{"_id":"$Name","Details":{$last:"$Details"}}}, {$project:{"Name":"$_id","Details":1}} ]);
这将产生以下输出-
{ "_id" : "John", "Details" : "Second 2:2", "Name" : "John" }