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Legal Studies如何在 MongoDB 的单个更新中使用 $set 和 $push？
为此，只需使用 update() 进行更新。让我们创建一个带有文件的集合 -
> db.dem0143.insertOne({"StudentId":1,"Details":{"Name":"Chris"}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e32eb9efdf09dd6d08539b7")
}
> db.dem0143.insertOne({"StudentId":2,"Details":{"Name":"David"}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e32eba5fdf09dd6d08539b8")
}在集合中使用 find() 方法显示所有文件 -
> db.dem0143.find();
这将产生以下输出 -
{ "_id" : ObjectId("5e32eb9efdf09dd6d08539b7"), "StudentId" : 1, "Details" : { "Name" : "Chris" } }
{ "_id" : ObjectId("5e32eba5fdf09dd6d08539b8"), "StudentId" : 2, "Details" : { "Name" : "David" } }以下是单次更新中实施 $set 和 $push 的查询 -
> db.dem0143.update({_id: ObjectId("5e32eba5fdf09dd6d08539b8")}, {$push: {StudentAge:21}, $set: {"Details.Name":"John Doe"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })在集合中使用 find() 方法显示所有文件 -
> db.dem0143.find();
这将产生以下输出 -
{ "_id" : ObjectId("5e32eb9efdf09dd6d08539b7"), "StudentId" : 1, "Details" : { "Name" : "Chris" } }
{ "_id" : ObjectId("5e32eba5fdf09dd6d08539b8"), "StudentId" : 2, "Details" : { "Name" : "John Doe" }, "StudentAge" : [ 21 ] }
更新时间: 31-Mar-2020
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