背景经常忘，经常查，倒不如我自己写一篇给自己方便参考，毕竟每次都在某N站查出来的都是不知道互抄到哪一年的机翻文章。本文涉及代码与测试参考unity版本为2021.3，AddForce用于对rigidbody组件对象添加力的作用。其参数决定了添加力的作用方式，因此参数不同，其获得的效果（动量、动能）也不同。另外unity重力加速度默认为9.81左右，随着物体的状况会有改变。使用Debug.Log("Gravity:"+Physics.gravity);查看重力加速度（重力加速度也有方向！所以也是Vector3）。要点你需要了解并理解以下内容力是矢量，有方向，因此调用时的第一个参数是Vector3
done_status=['BAD_PU','TO_WH','RCVDPORT','RCVD','BAD_DEL','MISSFLT','OFFLOAD']shipments=db.db_shipment.aggregate([{"$lookup":{"from":"db_shipment_status_history","localField":"_id","foreignField":"fk_shipment_id","as":"shipment_status_history_collection"}},{"$unwind":"$shipment_status_history_co
以如下数据为例:{_id:1,item:"abc",stock:[{size:"S",color:"red",quantity:25},{size:"S",color:"blue",quantity:10},{size:"M",color:"blue",quantity:50}]}{_id:2,item:"def",stock:[{size:"S",color:"blue",quantity:20},{size:"M",color:"blue",quantity:5},{size:"M",color:"black",quantity:10},{size:"L",color:"red",
问题是给定的文档有两个数组，每个数组都包含文档作为它们的元素，我想找到本质上具有的文档:"obj1.a"==="obj2.b"所以给定示例文档，但实际上期望更大的数组，那么该怎么做呢？:{"obj1":[{"a":"a","b":"b"},{"a":"a","b":"c"}],"obj2":[{"a":"c","b":"b"},{"a":"c","b":"c"}]},{"obj1":[{"a":"a","b":"b"}],"obj2":[{"a":"a","b":"a"}]}一种方法可能是将它们与JavaScript和$where进行比较运算符，但从JavaScript中循环大型数组听
假设我正在使用$unwind在Mongoose模式中的字段上根据上面的链接，如果字段不存在，则unwind将忽略输入文档我怎样才能防止这种情况发生，即使字段不存在，即不忽略输入文档，也不会在没有展开过程的情况下返回查询结果ifaparticularfieldexistsIwanttodounwindandsomemorestuff(projectandgroup)elseIwantinputdocumentnochangesinthiscase 最佳答案 AccordingtotheabovelinkIffieldisnotpres
我有以下数据集:{"_id":ObjectId("57684f2b61f2af6d49fa6dbd"),"firstname":"First1","surname":"Sur1","email":"first1@sur1.com","goals":[{"gId":"base1","recordDate":ISODate("2016-06-21T20:05:48.972Z")},{"gId":"base2","recordDate":ISODate("2016-06-21T20:05:48.972Z")},{"gId":"base1","recordDate":ISODate("2016
我在mongodb中有以下客户订单数据"_id":7,"customername":"JohnSmith","OrderItem":[{"product_category":"Mobile","price":900},{"product_category":"Computer","price":4200.48},{"product_category":"TV","price":670.20},{"product_category":"TV","price":960.52}]我需要对每个产品类别进行平均，如下所示:"_id":7,"customername":"JohnSmith","O
我有带有OrderItems的对象Order。我需要按字段ProductId(按orderItems)对数据进行分组并显示每个产品的总和。此解决方案效果很好:varcollection=database.GetCollection("Order");varresult=collection.Aggregate().Unwind(x=>x.OrderItems).Group(newBsonDocument{{"_id","$OrderItems.ProductId"},{"suma",newBsonDocument{{"$sum","$OrderItems.UnitPriceExclTa
我正致力于在MongoDB中开发一个管道，它将每个州的公司的所有number_of_employees相加，并打印出每个州的信息。集合结构的基本原理如下所示:"name":"AdventNet","number_of_employees":600,"offices":[{"description":"Headquarters","address1":"4900HopyardRd.","address2":"Suite310","zip_code":"94588","city":"Pleasanton","state_code":"CA","country_code":"USA","la
我有一个这样的集合:[{"_id":1,"OtherProperties":100"PersonInventory":[{"FirstName":"Joe","MiddleName":"Bob","LastName":"Blogs","PersonId":1}]},{"_id":2,"OtherProperties":1005"PersonInventory":[{"FirstName":"Joe","MiddleName":"Bob","LastName":"Blogs","PersonId":1}]}]我正在尝试使用此处较新的类型推断mongodbc#驱动程序语法来选择根文档中的所
