更新键值，其中另一个键等于MongoDB中的某个值？
将$elem与$set配合使用
首先让我们创建一个包含文档的集合-
> dbkeyValueDemoinsertOne(
{
"_id" : new ObjectId(),
"CustomerDetails" : [
{
"Name" : "Chris",
"Age" :24,
},
{
"Name" : "Robert",
"Age" :29,
},
{
"Name" : "David",
"Age" :35,
}
]
}
);
{
"acknowledged" : true,
"insertedId" : ObjectId("5cefcf36ef71edecf6a1f6bf")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> dbkeyValueDemofind()pretty();
输出结果
{
"_id" : ObjectId("5cefcf36ef71edecf6a1f6bf"),
"CustomerDetails" : [
{
"Name" : "Chris",
"Age" : 24
},
{
"Name" : "Robert",
"Age" : 29
},
{
"Name" : "David",
"Age" : 35
}
]
}这是更新键值的查询，其中不同的键等于某个值-
> dbkeyValueDemoupdate(
{"CustomerDetails":{"$elemMatch":{"Name":"David"}}},
{"$set":{"CustomerDetails$Age":56}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }
)让我们再次检查文档-
> dbkeyValueDemofind()pretty();
输出结果
{
"_id" : ObjectId("5cefcf36ef71edecf6a1f6bf"),
"CustomerDetails" : [
{
"Name" : "Chris",
"Age" : 24
},
{
"Name" : "Robert",
"Age" : 29
},
{
"Name" : "David",
"Age" : 56
}
]
}