在mongodb中，存在如下數據

{ "_id" : ObjectId("59af55078a8fc5e51ff425de"), "title" : "title1", "col" : "col
1", "reader" : [ { "readername" : "jim", "isread" : true }, { "readername" : "ka
te" }, { "readername" : "lilei" } ], "begindate" : "Wed Sep 06 2017 09:53:11 GMT
+0800 (中國標準時間)" }
{ "_id" : ObjectId("59af552e8a8fc5e51ff425df
 
"), "title" : "title2", "col" : "col
1", "reader" : [ { "readername" : "jim" }, { "readername" : "kate" }, { "readern
ame" : "lilei" }, { "readername" : "lily" } ], "begindate" : "Wed Sep 06 2017 09
:53:50 GMT+0800 (中國標準時間)" }
{ "_id" : ObjectId("59af55458a8fc5e51ff425e0"), "title" : "title3", "col" : "col
1
 
", "reader" : [ { "readername" : "jim" }, { "readername" : "kate" } ], "beginda
te" : "Wed Sep 06 2017 09:54:13 GMT+0800 (中國標準時間)" }

需求1：查詢欄目是col1，且讀者是lily的記錄：

> db.articles.find({col:‘col1‘,‘reader.readername‘:‘lily‘})
//查詢結果
{ "_id" : ObjectId("59af552e8a8fc5e51ff425df"), "title" : "title2", "col" : "
 
col
1", "reader" : [ { "readername" : "jim" }, { "readername" : "kate" }, { "readern
ame" : "lilei" }, { "readername" : "lily" } ], "begindate" : "Wed Sep 06 2017 09
:53:50 GMT+0800 (中國標準時間)" }

即數組中的對象用形如“數組名.字段”組成

需求2：把標題為title2，且讀者為lily的已讀記錄‘isread’設置為true

> db.articles.update({title:‘title2‘,‘reader.readername‘:‘lily‘},{$set:{‘reader.
$.isread‘:true}})

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

{ "_id" : ObjectId("59af552e8a8fc5e51ff425df"), "title" : "title2", "col" : "col
1", "reader" : [ { "readername" : "jim" }, { "readername" : "kate" }, { "readern
ame" : "lilei" }, { "readername" : "lily", "isread" : true } ], "begindate" : "W
ed Sep 06 2017 09:53:50 GMT+0800 (中國標準時間)" }

核心是$，可以理解為數組定位器

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mogodbshell中數組對象查詢修改方法