如何使用日期字段添加ToSet [英] How to addToSet with date field

问题描述

我在猫鼬中有以下模型:

I have following model in mongoose :

var RelationSchema = new Schema({
  user : {type:ObjectId, ref:'users'}
  , type : String
  , remarks : String
  , createdOn : {type:Date, default:Date.now}
}, {_id:false});

var UserRelationSchema = new Schema({
  user : {type:ObjectId, ref:'users'}
  , relations : [RelationSchema]
});

var UserRelation = mongoose.model('user_relations', UserRelationSchema);

每次我使用相同的值运行以下命令时，都会将一个新的子文档添加到 relations 数组中.如果我从 RelationSchema 模式中删除了 createdOn 字段，那么它工作正常.

Each time I run the following command with same values a new sub-document is being added to the relations array. If I removed createdOn field from the RelationSchema schema then it works fine.

UserRelation.update(
{"user":<ObjectId>} 
, {
    $addToSet: {
       "relations": {"user":<ObjectId>,"type":<String>}
    }
, {upsert:true}
});

我的问题是:如何使用日期/时间字段addToSet?

My Question is : How can I addToSet with date/time fields ?

推荐答案

要使 $addToSet 不添加元素，该元素必须完全匹配现有元素.createdOn 是当前时间，很容易看出为什么在您的情况下从未发生过.

For $addToSet to not add an element, the element must completely match an existing element. With createdOn being the current time it's easy to see why that never happens in your case.

所以 $addToSet 可以很好地处理带有 Date 字段的元素，但它需要完全匹配，就像任何其他类型一样.

So $addToSet works fine for elements with Date fields, but it requires an exact match, just like with any other type.

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