带有@MappedSuperclass的Hibernate TABLE_PER_CLASS不会创建UNION查询 [英] Hibernate TABLE_PER_CLASS with @MappedSuperclass won't create UNION query

问题描述

我正在尝试创建一系列对象，这些对象都存储在单独的表中，但是所有这些表上都有一组共同的字段.我希望Hibernate对所有这些表都做一个UNION，但不要将超类包含在表中.

I am trying to create a series of objects that all are stored in separate tables, but that there is a set of fields in common on all these tables. I want Hibernate to do a UNION of all these tables, but NOT INCLUDE the superclass as a table.

当我用以下方法注释超类时:@MappedSuperclass@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)

When I annotate the superclass with just: @MappedSuperclass @Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)

... hibernate将针对超类的(n)个子类型分别运行(n)个查询.

...hibernate will run (n) queries separately for the (n) subtypes of the superclass.

当我删除@MappedSuperclass而不是将@Entity放在超类上时，Hibernate会执行精美的UNION查询，但会将超类作为表包含在UNION中(超类没有表).

When I remove @MappedSuperclass and instead put @Entity on the super class, Hibernate WILL do the fancy UNION query, but includes the superclass as a table in the UNION (there is no table for the superclass).

如何在不将父类设为@Entity的情况下将所有子类(不是单独的查询)放到UNION中(因为它不是实体，所以没有用于它的表)?

How do I get it to UNION together all the subclasses (not separate queries) without making the parent class an @Entity (because it's not an entity, there's no table for it)?

推荐答案

我发现将父类标记为抽象"可以解决问题，Hibernate不再将其包含在UNION中，并且 did UNION所有子类.

I found that marking the parent class as "abstract" did the trick, Hibernate no longer included it in the UNION and did UNION together all the sub-classes.

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