HQL查询以从@ElementCollection获取字段 [英] HQL Query to get fields from @ElementCollection

问题描述

我正在尝试构造一个HQL查询以从@ElementCollection中提取属性:

I'm trying to construct an HQL query to pull properties from an @ElementCollection:

public class Resource {
  @Id
  private String name;

  @ElementCollection()
  @CollectionTable(
          name = "property",
          )
  @SortNatural
  private final SortedMap<String, String> properties =
        Maps.newTreeMap();
}

property表使用默认列名(properties和properties_key)来存储数据(使用外键返回我的资源表).

The property table is using the default column names (properties and properties_key) to store the data (with a foreign key back to my resource table).

我有以下HQL查询，正在尝试返回键和值.

I have the following HQL query, where I'm trying to return the keys and values.

final Query q = session.createQuery("select new list(r.name, elements(r.properties)) from Resource r where r.name like :nameFilter");

这是有效的，当我调用q.list()时，我得到一个包含名称和值的对象列表.我遇到的问题是我无法弄清楚如何获取与值关联的键.即properties_key列中的数据.

This is working, and when I call q.list(), I get a List of objects containing the name and values. The problem I'm having is that I can't figure out how to get the keys which are associated with the values. i.e. The data in the properties_key column.

我尝试过的事情:

1. 元素(r.properties_key)
2. 元素(r.propertiesKey)
3. 元素(r.key)

没有一项工作.

是否可以获取此数据?如何确定要在HQL查询中使用的属性的名称?

Is it possible to get this data out? How can I figure out the name of the property to use in my HQL query?

推荐答案

加入集合，然后使用 index()获取密钥.
index(p)是键，而 p 是值.

Join the collection and then use index() to get the key.
index(p) is the key and p is the value.

List list = currentSession.createQuery(
"select new list(s.id, index(p), p) from Resource s join s.properties p").list();

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