[英]Hibernate FetchMode.JOIN with one to many mapping
有兩個實體 InvoiceHeader 和 InvoiceDetail 具有一對多映射,如下所示。
發票頭
@Entity
@Table(name = "view_invoice_hdr")
@IdClass(InvoiceHdrPK.class)
@Getter
@NoArgsConstructor
@EqualsAndHashCode
public class InvoiceHeader{
....
@OneToMany(mappedBy = "invoiceHeader", fetch = FetchType.EAGER)
@Fetch(value = FetchMode.JOIN)
private List<InvoiceDetail> items;
}
發票HdrPK
@Getter
@ToString
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode
public class InvoiceHdrPK implements Serializable {
private String invoiceNumber;
private InvoiceSource invoiceSource;
private InvoiceType invoiceType;
private Long companyId;
private Integer invoiceYear;
}
同樣InvoiceDetail
@Entity
@Table(name = "view_inv_dtl")
@IdClass(InvoiceDetailPK.class)
@Getter
@NoArgsConstructor
@EqualsAndHashCode
public class InvoiceDetail{
....
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumns(value = {
@JoinColumn(name = "invoice_number", referencedColumnName = "invoice_number", insertable = false, updatable = false),
@JoinColumn(name = "invoice_source", referencedColumnName = "invoice_source", insertable = false, updatable = false),
@JoinColumn(name = "invoice_type", referencedColumnName = "invoice_type", insertable = false, updatable = false),
@JoinColumn(name = "company_id", referencedColumnName = "company_id", insertable = false, updatable = false),
@JoinColumn(name = "invoice_year", referencedColumnName = "invoice_year", insertable = false, updatable = false),
})
private InvoiceHeader invoiceHeader;
}
發票明細PK
@Getter
@ToString
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode
public class InvoiceDetailPK implements Serializable {
private String invoiceNumber;
private InvoiceSource invoiceSource;
private InvoiceType invoiceType;
private BigDecimal rate;
private Long itemNo;
private Long companyId;
private Integer invoiceYear;
}
這兩個實體都不是數據庫級別的實際表,而是作為視圖維護。
使用 JPA我正在嘗試使用帶有FetchMode.JOIN的findAll(Specification, pageable)來獲取發票以避免n+1查詢問題。
但得到異常
org.hibernate.QueryException: query specified join fetching, but the owner of the fetched association was not present in the select list...
那么我該如何解決這個問題,我錯過了什么?
也許你使用 Set 而不是 List @OneToMany(mappedBy = "invoiceHeader", fetch = FetchType.EAGER) @Fetch(value = FetchMode.JOIN) private Set items = new HashSet<>();
似乎您使用類似於此select b from A a join ab b join fetch a.c
的查詢。 要點是,您加入獲取一些您從未通過 select 子句中的父項引用的關聯。
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