草庐IT

mongodb - 如何在 mongodb 中聚合查询

我有一个如下所示的文档集合:{name:"tester",activity:[{gear:"glasses"where:"outside"},{gear:"hat",where:"inside"},{gear:"glasses",where:"car"}]}如何查询集合以仅返回具有包含“gear”:“glasses”值的多个事件的文档?谢谢! 最佳答案 如果您需要按您的条件过滤的完整文档,我认为可以不用聚合框架:db.collection.find({"activity":{$elemMatch:{gear:"glasses"}},

接口(interface)和将匿名字段嵌入到结构中

当附近发生爆炸时,我试图代表一个戴着眼镜的人靠近window。main是爆炸期间应​​该做什么的草图。有些东西应该收集爆炸附近的物体列表,并为每个物体做特定的事情(例如粉碎或熔化)。玻璃和window如预期般碎裂,但出于某种原因,人也碎裂了。为什么?packagemainimport"fmt"typeHumanstruct{Glasses}typeGlassesstruct{}typeShatterableinterface{shatter()}func(gGlasses)shatter(){}typeWindowstruct{}func(wWindow)shatter(){}func

接口(interface)和将匿名字段嵌入到结构中

当附近发生爆炸时,我试图代表一个戴着眼镜的人靠近window。main是爆炸期间应​​该做什么的草图。有些东西应该收集爆炸附近的物体列表,并为每个物体做特定的事情(例如粉碎或熔化)。玻璃和window如预期般碎裂,但出于某种原因,人也碎裂了。为什么?packagemainimport"fmt"typeHumanstruct{Glasses}typeGlassesstruct{}typeShatterableinterface{shatter()}func(gGlasses)shatter(){}typeWindowstruct{}func(wWindow)shatter(){}func

Get ready! Experience the Future Through AR Glasses

Thepurposeofaugmentedrealityistocombinethephysicalandvirtualworlds.Asthecornerstoneofthenextvirtualworld,XRgadgetshavesuddenlycaughttheattentionofbigtechnologycorporationsasthemetaversebecomesincreasinglypopular.Asatechnologybusinessspecializinginhuman-computerinterfacetechnologyandAIhardwareR&D,Rok

Get ready! Experience the Future Through AR Glasses

Thepurposeofaugmentedrealityistocombinethephysicalandvirtualworlds.Asthecornerstoneofthenextvirtualworld,XRgadgetshavesuddenlycaughttheattentionofbigtechnologycorporationsasthemetaversebecomesincreasinglypopular.Asatechnologybusinessspecializinginhuman-computerinterfacetechnologyandAIhardwareR&D,Rok