更新MongoDB中的数组元素？
使用$addToSet运算符更新数组元素。首先让我们创建一个包含文档的集合-
> db.updateArrayDemo.insertOne(
... {
...
... "ClientDetails" : [
... {
... "ClientName" : "John",
... "DeveloperDetails" : [ ]
... },
... {
... "ClientName" : "Larry",
... "DeveloperDetails" : [ ]
... }
... ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5ccf465edceb9a92e6aa1960")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.updateArrayDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5ccf465edceb9a92e6aa1960"),
"ClientDetails" : [
{
"ClientName" : "John",
"DeveloperDetails" : [ ]
},
{
"ClientName" : "Larry",
"DeveloperDetails" : [ ]
}
]
}以下是更新数组元素的查询-
> db.updateArrayDemo.update({ "ClientDetails.ClientName": "Larry" },
{ $addToSet: { "ClientDetails.$.Technology": { 'DeveloperName': "Chris", 'WorkExperience':5 } } }, false, true);
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })让我们检查数组元素是否已更新-
> db.updateArrayDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5ccf465edceb9a92e6aa1960"),
"ClientDetails" : [
{
"ClientName" : "John",
"DeveloperDetails" : [ ]
},
{
"ClientName" : "Larry",
"DeveloperDetails" : [ ],
"Technology" : [
{
"DeveloperName" : "Chris",
"WorkExperience" : 5
}
]
}
]
}