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我目前正在将 GraphQL SPQR 与 Spring Boot 一起使用。为了提高数据库性能，我使用@GraphQLEnvironment ResolutionEnvironmentfrom this 编写了自定义逻辑，我已经能够找到所有请求的值并为@Entity注释过滤它们，然后我使用这些来创建一个动态 EntityGraph 用于 Eager fetch 那些特定的价值观。

现在，这似乎适用于映射的实体，@OneToMany因为我@ManyToOne和@OneToOne实体仍然会进行单独的 Hibernate SQL 查询，即使它们没有被选中（当它们被选中时，它们会被急切地提取为连接）。

我尝试了很多不同的东西，例如 Hibernate Enhanced Bytecode 和使用 LazyInitilization 确实会停止加载这些实体 - 但是当它们被选中时，它似乎也进行了一个 Join 和一个单独的选择查询。

Hibernate: 
    /* select
        generatedAlias0 
    from
        OwningJob as generatedAlias0 
    where
        generatedAlias0.jobNumber=:param0 */ select
            owningjob0_.pkId as pkid1_13_0_,
            customer1_.customerPkId as customer1_0_1_,
            owningjob0_.customerCode as customer7_13_0_,
            ...
        from
            dbo.OwningJob owningjob0_ 
        left outer join
            dbo.Customer customer1_ 
                on owningjob0_.CustomerCode=customer1_.customerId 
        where
            owningjob0_.OwningJobId=?
Hibernate: 
    /* sequential select
        uk.co.essl.jobloadapi.model.jobapi.OwningJob */ select
            owningjob_.CustomerCode as customer7_13_ 
        from
            dbo.OwningJob owningjob_ 
        where
            owningjob_.pkId=?

我不知道为什么会发出额外的选择请求，似乎 Hibernate 很困惑，因为它已经被急切地加载了？

这也导致了 N+1 问题，关于出了什么问题的任何想法。我也对完全不同的方法持开放态度！

实体类的一部分：

@Entity
@Table(name = "OwningJob", schema = "dbo")
@GraphQLType(name = "Order", description = "Order description.")
@Getter
public class OwningJob {

  @ManyToOne
  @JoinColumn(name = "CustomerCode", referencedColumnName = "CustomerId")
  @LazyToOne(LazyToOneOption.NO_PROXY)
  @LazyGroup("owningJob_customer")
  public Customer customer;

}

编辑：

我现在尝试使用 JPA Criteria API，但我似乎仍然得到相同的行为：

    CriteriaBuilder builder = entityManager.getCriteriaBuilder();
    CriteriaQuery<Object> criteria =  builder.createQuery(Object.class);
    Root<OwningJob> root = criteria.from(OwningJob.class);

    Path<String> customerReference = root.get("customerReference");
    Path<String> jobNumber_ = root.get("jobNumber");
    Path<Object> customerPath = root.join("customer");

    criteria = criteria
        .multiselect(customerReference, jobNumber_, customerPath)
        .where(builder.equal(root.get("jobNumber"), jobNumber));

这导致这两个查询都被触发......

Hibernate: 
    select
        owningjob0_.customerReference as col_0_0_,
        owningjob0_.OwningJobId as col_1_0_,
        customer1_.customerPkId as col_2_0_,
        customer1_.customerPkId as customer1_0_,
        customer1_.customerId as customer2_0_,
        customer1_.customerName as customer3_0_ 
    from
        dbo.OwningJob owningjob0_ 
    inner join
        dbo.Customer customer1_ 
            on owningjob0_.CustomerCode=customer1_.customerId 
    where
        owningjob0_.OwningJobId=?
Hibernate: 
    select
        customer0_.customerPkId as customer1_0_0_,
        customer0_.customerId as customer2_0_0_,
        customer0_.customerName as customer3_0_0_ 
    from
        dbo.Customer customer0_ 
    where
        customer0_.customerId=?
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