第一步：加入部门集合 第二步：Map生成的Array对象，并根据条件进行合并 Mongodb聚合管道：https://mong...
$lookup: { from: <collection to join>, localField: <field from the input documents>, foreignField: <field from the documents of the "from" collection>, as: } } 示例: 假设有两个集合,一个是订单集合orders,另一个是用户集合users,现在你想关联这两个集合以获取每个订单的用户信息。 db.orders....
当$unwind后面紧跟着另一个$lookuo,并且$unwind操作的字段同$lookup一致,这优化器会将$unwind合并到$lookup中。这样可以减少创建大的临时文档。 如有如下管道示例: { $lookup: { from: "otherCollection", as: "resultingArray", localField: "x", foreignField: "y" } }, { $unwind: "$resultingArray"}...
indexes Array 選擇性設定索引。 只有 3.6+ 的帳戶支援此參數。 有此參數時,需要 _id 的索引。 陣列中的每個項目都必須包含一個或多個欄位的索引鍵、名稱,還可能包含索引選項。 例如,若要在欄位 a 和b 上建立複合唯一索引,請輸入:{key: {a: 1, b: 1}, name:"a_1_b_1", unique: true}。輸出...
Type: array of objects(AdditionalColumns) (or Expression with resultType array of objects). Parameters: additionalColumns - the additionalColumns value to set. Returns: the CosmosDbMongoDbApiSource object itself.withBatchSize public CosmosDbMongoDbApiSource withBatchSize(Object batchSize) Set the ...
documents documents array of object documents items documents object Insert Document Operation ID: InsertDocument Using the insertOne endpoint, you can add a document to a collection. Use the document property in the request body to specify the document that should be created. Parameters Раз...
$documentsaccepts any valid expression that resolves to an array of objects. This includes: system variables, such as$$NOWor$$SEARCH_META $letexpressions variables in scope from$lookupexpressions Expressions that do not resolve to a current document, like$myFieldor$$ROOT, will result in an erro...
优化器可以把$unwind阶段合并至$lookup阶段。如果你用explain选项运行这个聚集,explain输出如下的合并阶段: { $lookup: { from: "otherCollection", as: "resultingArray", localField: "x", foreignField: "y", unwinding: { preserveNullAndEmptyArrays: false } ...
{ "arrayFilters" : NumberLong(0), "failed" : NumberLong(0), "pipeline" : NumberLong(23063), "total" : NumberLong(511271) }, "usersInfo" : { "failed" : NumberLong(0), "total" : NumberLong(1) }, "whatsmyuri" : { "failed" : NumberLong(0), "total" : NumberLong(5) } }, "...
SERVER-18794: Add an aggregation operator $objectToArray to convert an object to an array of key, value pairs. SERVER-23310: Add an aggregation operator $arrayToObject to convert an array of pairs to an object. SERVER-22611: ChunkManager refresh can occasionally cause a full reload. 3.4.4...