Spring Data - 为什么不能使用本机查询进行分页 [英] Spring Data - Why it's not possible to have paging with native query
问题描述
假设我们有一个名为 MyEntity 的实体。可以使用 @Query 和命名查询来查询可分页结果，例如
Let's say we have an entity called MyEntity. It is possible to query pageable results using @Query and with named queries, e.g.
@Query(value = "select e from MyEntity e where e.enabled = true")
Page<MyEntity> findAllEnabled(Pageable pageable);
但是，使用本机查询无法实现相同的功能，所以这个
However, it is not possible to achieve the same with native query, so this
@Query(value = "select * from my_entity where enabled = true", nativeQuery = true)
Page<MyEntity> findAllEnabled(Pageable pageable);
不起作用。
这背后的原因是什么？是否可以使Pageable使用本机查询？
What are the reasons behind this? Is it possible to make Pageable working with native queries?
推荐答案
这是描述，在spring data jpa文档中给出（ http://docs.spring.io/spring-data /jpa/docs/1.8.0.M1/reference/html/ ）
This is description, given in spring data jpa documentation (http://docs.spring.io/spring-data/jpa/docs/1.8.0.M1/reference/html/)
原生查询@Query注释允许执行native将nativeQuery标志设置为true，从而查询
。注意，我们目前没有
支持对本机查询执行分页或动态排序
，因为我们必须操纵声明的实际查询，我们无法为本机SQL可靠地执行
。
Native queriesThe @Query annotation allows to execute native queries by setting the nativeQuery flag to true. Note, that we currently don’t support execution of pagination or dynamic sorting for native queries as we’d have to manipulate the actual query declared and we cannot do this reliably for native SQL.
JPQL抽象SQL实现及其提供者细节，并使ORM框架负责生成正确的SQL。
JPQL abstracts SQL implementation and it's providers specifics, and makes it responsibility of ORM framework to generate correct SQL.
-
因此，通过在JPQL表单中使用分页，Spring只需要生成正确的JPQL，它将在ORM级别上进行解释以纠正SQL。
So by using Pagination in JPQL form, Spring just needs to generate correct JPQL, and it will be interpreted on ORM level to correct SQL.
使用SQL这样做意味着Spring知道如何为大量的RDBMS生成正确的SQL，复制ORM功能，这是一个过多的开销。 / p>
While doing so with SQL, would imply that Spring knows how to generated correct SQL for the vast majorities of RDBMS, duplicating ORM functionality, which is too much overhead.
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