使用nodejs/mongoose部分更新子文档 [英] Partial update of a subdocument with nodejs/mongoose
问题描述
使用Mongoose可以一次性在(子)文档上设置多个属性吗?我正在尝试做的事的一个例子:
Is it possible to set multiple properties on a (sub)document in one go with Mongoose? An example of what I'm trying to do:
比方说我有这个模式:
var subSchema = new Schema({
someField: String,
someOtherField: String
});
var parentSchema = new Schema({
fieldOne: String,
subDocs: [subSchema]
})
那我想做:
exports.updateMyDocument = function(req, res) {
var parentDoc = req.parentDoc; // The parent document. Set by parameter resolver.
var document = req.myDoc; // Sub document of parent. Set by parameter resolver.
var partialUpdate = req.body; // updated fields sent as json and parsed by body parser
// I know that the statement below doesn't work, it's just an example of what I would like to do.
// Updating only the fields supplied in "partialUpdate" on the document
document.update(partialUpdate);
parentDoc.save(function(err) {
if(err) {
res.send(500);
return;
}
res.send(204);
});
};
通常,我可以使用$set
运算符来实现此目的,但是我的问题是本示例中的document
是parentDoc
的子文档(嵌入式架构).所以当我尝试做
Normally, I could achieve this using the $set
operator, but my problem is that document
in this example is a subdocument (embedded schema) of parentDoc
. So when I tried to do
Parent.update({_id: parentDoc._id, "subDocs._id": document._id},
{$set: {"subDocs.$" : partialUpdate}},
function(err, numAffected) {});
它替换了subDocs._id
标识的子文档实例.目前,我已经通过手动设置仅字段来解决"了该问题,但我希望有一种更好的方法.
it replaced the subdocument instance identified by subDocs._id
. Currently I have "solved" it by setting only fields manually, but I was hoping for a better way to do this.
推荐答案
基于partialUpdate
的字段以编程方式构建$set
对象,以使用点表示法仅更新这些字段:
Build up a $set
object programmatically based on the fields of partialUpdate
to update just those fields using dot notation:
var set = {};
for (var field in partialUpdate) {
set['subDocs.$.' + field] = partialUpdate[field];
}
Parent.update({_id: parentDoc._id, "subDocs._id": document._id},
{$set: set},
function(err, numAffected) {});
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