WebMongoDB is a document database. It stores data in a type of JSON format called BSON. If you are unfamiliar with JSON, check out our JSON tutorial. A record in MongoDB is a document, which is a data structure composed of key value pairs similar to the structure of JSON objects. Start learning MongoDB now ». Web5 jun. 2024 · If you notice one thing, the product is inflated, but its an array instead of an object. The reason being, mongodb expects that multiple documents in the products table may match with this criteria, and hence by default puts all the docs in an array. In our case we know its going to be unique, so we can just unwind it out.
mongodb unwind array nested inside an array of documents
WebMongoDB Web下面給出的是我的mongodb集合中的三個文檔， 注意： 我在文檔中的 廣告系列名稱 字段中定義了各種廣告系列，然后在每個廣告系列中都有多個Adsets 廣告集名稱 ，然后在每個adset 廣告集名稱 中都有多個ads 廣告名 表示每個廣告必須屬於一個廣告集 廣告集名稱 ，每個廣告集 廣告集名稱 都 saxonmathresources
$unwind (aggregation) — MongoDB Manual
Web14 sep. 2016 · MongoDB aggregation gets exponentially complicated by the minute! I am in so far as to $unwind a nested array and then perform a $lookup by the _id of each … Web1 dec. 2024 · As you can see, unwind is a great way to pull arrays out from within your documents so aggregation can work with the data inside them. Paired with group, it offers the ability to radically reshape your data so you can extract new insight from it. How helpful was this article? About The Author Dj Walker-Morgan Web23 sep. 2016 · Seems like you have multiple nested objects. In your case if you consider the total arrays that will be unwinded to get 1 hour data, it will be : 1*60*60 = 3600. Also, … scales and key signatures