如何更新MongoDB _id集合

要更新_id，请在MongoDB中使用$set。让我们创建一个包含文档的集合-

db.demo741.insertOne({SubjectName:"MySQL"}); { "acknowledged" : true, "insertedId" : ObjectId("5ead718657bb72a10bcf0672") } > db.demo741.insertOne({SubjectName:"C"}); { "acknowledged" : true, "insertedId" : ObjectId("5ead718957bb72a10bcf0673") } > db.demo741.insertOne({SubjectName:"Java"}); { "acknowledged" : true, "insertedId" : ObjectId("5ead718e57bb72a10bcf0674") }

在find()方法的帮助下显示集合中的所有文档-

> db.demo741.find();

这将产生以下输出-

{ "_id" : ObjectId("5ead718657bb72a10bcf0672"), "SubjectName" : "MySQL" } { "_id" : ObjectId("5ead718957bb72a10bcf0673"), "SubjectName" : "C" } { "_id" : ObjectId("5ead718e57bb72a10bcf0674"), "SubjectName" : "Java" }

以下是更新_id的MongoDB的查询-

>db.demo741.update({_id:ObjectId("5ead718957bb72a10bcf0673")},{$set:{SubjectName:"PL/SQL"}}); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

在find()方法的帮助下显示集合中的所有文档-

> db.demo741.find();

这将产生以下输出-

{ "_id" : ObjectId("5ead718657bb72a10bcf0672"), "SubjectName" : "MySQL" } { "_id" : ObjectId("5ead718957bb72a10bcf0673"), "SubjectName" : "PL/SQL" } { "_id" : ObjectId("5ead718e57bb72a10bcf0674"), "SubjectName" : "Java" }