如何在MongoDB中更新JSON列表中的键值？
首先让我们创建一个包含文档的集合
> db.updateListOfKeyValuesDemo.insertOne( { "StudentDetails":[ { "StudentName":"John", "StudentAge":23, "StudentCountryName":"US" }, { "StudentName":"Carol", "StudentAge":24, "StudentCountryName":"UK" }, { "StudentName":"Bob", "StudentAge":22, "StudentCountryName":"AUS" } ] } );
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9b5b759882024390176545")
}以下是在find()方法的帮助下显示集合中所有文档的查询
> db.updateListOfKeyValuesDemo.find().pretty();
这将产生以下输出
{
"_id" : ObjectId("5c9b5b759882024390176545"),
"StudentDetails" : [
{
"StudentName" : "John",
"StudentAge" : 23,
"StudentCountryName" : "US"
},
{
"StudentName" : "Carol",
"StudentAge" : 24,
"StudentCountryName" : "UK"
},
{
"StudentName" : "Bob",
"StudentAge" : 22,
"StudentCountryName" : "AUS"
}
]
}以下是更新MongoDB中json列表中的键值的查询
> var documentFromCollection = db.updateListOfKeyValuesDemo.findOne({
... "_id": ObjectId("5c9b5b759882024390176545")
... });
>
> documentFromCollection.StudentDetails.forEach(function(updateStudent) {
... updateStudent.StudentName = "Ramit";
... });
> db.updateListOfKeyValuesDemo.update(
... { "_id": documentFromCollection ._id },
... { "$set": { "StudentDetails": documentFromCollection.StudentDetails } }
... );
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })让我们检查键值列表是否已更新
> db.updateListOfKeyValuesDemo.find().pretty();
这将产生以下输出
{
"_id" : ObjectId("5c9b5b759882024390176545"),
"StudentDetails" : [
{
"StudentName" : "Ramit",
"StudentAge" : 23,
"StudentCountryName" : "US"
},
{
"StudentName" : "Ramit",
"StudentAge" : 24,
"StudentCountryName" : "UK"
},
{
"StudentName" : "Ramit",
"StudentAge" : 22,
"StudentCountryName" : "AUS"
}
]
}