JPA / JPQL:根据相关对象的集合/地图填充集合/地图? (原型样) [英] JPA/JPQL: Fill a collection/map based on related object's collection/map? (prototype-like)
问题描述
我有这样的实体结构:
产品1 - > N ProductCustomField
1 1
| |
M M'
第1版 - > N'ReleaseCustomField
ProductCustomField
原型 - Release的字段列表。
我想选择一个 Release
对象所有 ReleaseCustomFields
其中 ProductCustomField
位于 Product
中,其中 Release
是。
示例: MySoft具有自定义字段downloadURL,其默认值为。 喜欢让MySoft 1.0发布一个包含downloadURL的地图(默认值为)。 我知道我会在SQL中做什么,它将是一个很好的复杂的SELECT,但可能。 不确定如果这是在 <我选择了第三种方法,因为我使用Wicket框架,所以我创建了一个Model,它给出 我开始获取 I have such structure of entities: I'd like to select a single Example: MySoft has custom field "downloadURL" with default value "".
MySoft has release 1.0.
This release has no ReleaseCustomFields, but because it is a release of MySoft, I can tell that it may have "downloadURL" custom field. So I would like to have MySoft 1.0 release with a map where "downloadURL" would be defined (with a default value ""). I know what would I do in SQL, it would be a nice long complex SELECT, but possible. Not sure if this is the right thing to try to achieve in I have chosen the third approach. Since I use the Wicket framework, I have created a Model which, given a I started getting 这篇关于JPA / JPQL:根据相关对象的集合/地图填充集合/地图? (原型样)的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
$ b
MySoft的版本为1.0。
这个版本没有ReleaseCustomFields,但是因为它是MySoft的一个版本,所以我可以说它可能有downloadURL的自定义字段。
我不知道如何在JPA / Hibernate中掌握它。
SELECT
中尝试实现的正确方法。
也许我应该用INSERT填充 Release
的自定义字段,然后简单地依赖映射(已经可用)?
还是应该在 Release
中创建一个特殊属性,并填写特殊查询? (我不介意使用 org.hibernate。*
注释。)
或者我应该做最简单的事情 - 以对
并执行操作,使用 ProductCustomField
中的每个字段使用release.getProduct()。getCustomFields() ReleaseCustomField
或
ProductCustomField#getDefault()
否则?
release
和 release.getProduct。 getCustomFields()。get(fieldName)
能够获取默认值或实际值,写入时更新 releases
'field values map。
IllegalArgumentException:object不是声明class
的实例,但这很可能一个不同的问题。Product 1 -> N ProductCustomField
1 1
| |
M M'
Release 1 -> N' ReleaseCustomField
ProductCustomField
is kind of "prototype" - a list of fields which Release may have.Release
object with all ReleaseCustomFields
whose ProductCustomField
are in the Product
of which the Release
is.
I don't know though how to grasp it in JPA/Hibernate.SELECT
.
Maybe I should rather fill the Release
's custom fields with an INSERT and then simply rely on mapping (which already works)?
Or should I create a special property in Release
, filled with special query? (I don't mind using org.hibernate.*
annotations.)
Or should I do the simplest thing - take release.getProduct().getCustomFields()
and do "for each field in ProductCustomField
, use what's in ReleaseCustomField
, or ProductCustomField#getDefault()
otherwise?release
and release.getProduct.getCustomFields().get("fieldName")
is capable of getting either default value, or the actual value, and when written to, updates releases
' field values map.IllegalArgumentException: object is not an instance of declaring class
but that's most likely a different problem.