问题:
我尝试查看文档数组中的对象并更新它。
下面的语法给了我想要的对象,但我不知道如何更新这个对象。我尝试在 findAndModify 中使用此语句,但似乎我无法在 findAndModify 方法中使用 $elemMatch
db.users.find({"username":"username"},{"array":{$elemMatch:{"name":"name"}}})
我尝试更改的示例 JSON
[{
"_id": ObjectId("5501b8fb77382c23704543fd"),
"username": "ker",
"password": "ker",
"character": "pet",
"visits": [],
"pets": [{"name": "Jura", "kind": "dog", "age": "2"}, {"name": "Ala", "kind": "dog", "age": "5"}]
}, {
"_id": ObjectId("5501b8fb77382c23704543fd"),
"username": "mer",
"password": "mer",
"character": "pet",
"visits": [],
"pets": [{"name": "Ita", "kind": "cat", "age": "6"}, {"name": "Esa", "kind": "cat", "age": "1"}]
}]
摘要:
我必须在集合中查找文档,然后在文档的数组中查找对象并更新该对象。
所以我的逻辑是这样的
db.collection.findAndModify({query:{Find Document In Collection THEN in document's array(pets) find object}, update:{$set:{New Values For Object}}})
最佳答案
您可以运行以下查询来实现您正在寻找的内容:
//findAndModify will always refer to one document
db.collection.findAndModify({
//Find the desired document based on specified criteria
query: { username: 'mer', pets: { $elemMatch: { name: 'Esa'}}},
//Update only the elements of the array where the specified criteria matches
update: { $set: { 'pets.$.name': 'CHANGED'}}
});
此查询将更新第二个文档:
{
"username" : "mer",
"password" : "mer",
"character" : "pet",
"visits" : [ ],
"pets" : [
{
"name" : "Ita",
"kind" : "cat",
"age" : "6"
},
{
"name" : "CHANGED",
"kind" : "cat",
"age" : "1"
}
]
}
您可以阅读有关使用 $
位置运算符 here 更新文档的更多信息。
关于javascript - MongoDB 查找并修改 : >>> find and update object in document's array,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29015665/