Morphia-基于子文档的查询 [英] Morphia - Query based on a subdocument

问题描述

我有一个mongo集合，其中包含如下文件:

I have a mongo collection which has documents which look like below :

{
"_id" : ObjectId("9873214jkhdkfjdsf8324"),
"nm" : "test",
"sts" : 1,
"updby" : NumberLong(0),
"tags" : [ 
    {
        "name" : "women", 
        "rank" : 1, 
        "type" : 3 
    }, 
    {
        "name" : "men",
        "rank" : 1
    }, 
    {
        "name" : "clothing",
        "rank" : 2,
        "type" : 1
    }
]

}

我要查询集合，以便要返回的每个文档的标签子文档中所有具有名称":"women"和"type":3的文档.

I want to query the collection such that I want all the documents which have "name": "women" and "type" : 3 inside the tags subdocument of each document which is returned.

我知道mongo查询应该是这样的:

I know that the mongo query should be something like this :

db.collection.find("tags":{
            $all:[
                {"$elemMatch":{"name":"women","type":3}},               
            ]})

我尝试使用了morphia提供的'hasthiselement'，但是我无法形成我想要的确切查询.

I tried using the 'hasthiselement' provided by morphia, but I am not able to form the exact query which I want.

 getMongoDAORead().getDatastore().createQuery(test.class)
                .field("tags").hasThisElement("name").equal("women");

此查询似乎不正确.有人可以帮助我形成正确的查询吗?

This query doesn't seem to be correct. Can someone help me form the correct query?

推荐答案

我通过以下操作解决了此问题:

I fixed this by doing the following:

我创建了标签类的对象并对其进行了初始化:

I created a object of the Tags Class and initialized it:

Tags tag = new Tags("women", null, 3);

Query<MyClass> t = getMongoDAORead().getDatastore()
        .createQuery(MyClass.class)
        .field("ctags").hasThisElement(tag);

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