java - Hibernate 中是否可能存在多个自然标识符组合？

Question

请考虑以下示例:

import org.hibernate.annotations.NaturalId;

import javax.persistence.Column;
import javax.persistence.Table;

@javax.persistence.Entity
@Table(name = "Entity", uniqueConstraints = {
        @javax.persistence.UniqueConstraint(columnNames = {"firstNaturalId"}),
        @javax.persistence.UniqueConstraint(columnNames = {"secondNaturalIdPart1", "secondNaturalIdPart2"})
})
class Entity {

    @NaturalId
    @Column(name = "firstNaturalId")
    private String firstNaturalId;

    @NaturalId
    @Column(name = "secondNaturalIdPart1")
    private String secondNaturalIdPart1;

    @NaturalId
    @Column(name = "secondNaturalIdPart2")
    private String secondNaturalIdPart2;

    // The remainder is omitted.

}

所需的功能是能够通过提供 ('firstNaturalId') 或 ('secondNaturalIdPart1', 'secondNaturalIdPart2') 组来检索唯一标识的实体.

在 Hibernate 中是否可能有几个自然标识符组合(组)来唯一标识表中的实体？

Answer 1

好久不见。也许你已经找到了答案。我心里有这个疑问。发现你的问题没有答案。搜索了更多。找到这个Natural Id Mapping .

public class Entity{
    
    @NaturalId @Embedded
    private EntityNI entityNI;

    public Entity(){}
    
//    Setter and Getter is omitted
//    .
//    .
//    .

    @Override
    public int hashCode(){
        return (entityNI != null ? entityNI.hashCode() : 31);
    }

    @Override
    public boolean equals(final Object object){
        if(this == object){
            return true;
        }
        if( !(object instanceof Entity) || (getClass() != object.getClass()) ){
            return false;
        }
        return this.entityNI.equals( ((Entity)object).entityNI );
    }
}

以及嵌入的自然 ids:

@Embeddable
public class EntityNI{
    
    @NotBlank @Basic(optional = false) @Column(name = "firstNaturalId")
    private String firstNaturalId;

    @NotBlank @Basic(optional = false) @Column(name = "secondNaturalIdPart1")
    private String secondNaturalIdPart1;

    @NotBlank @Basic(optional = false) @Column(name = "secondNaturalIdPart2")
    private String secondNaturalIdPart2;
    
    public EntityNI(){}
    
//    Setters and Getters are omitted
//    .
//    .
//    .

    @Override
    public int hashCode(){
        return Objects.hash(firstNaturalId, secondNaturalIdPart1, secondNaturalIdPart2);
    }

    @Override
    public boolean equals(Object object){
        if(this == object){
            return true;
        }
        if( !(object instanceof EntityNI) || (getClass() != object.getClass()) ){
            return false;
        }
        final EntityNI other = (EntityNI) object;
        return (this.firstNaturalId == other.firstNaturalId) && (this.secondNaturalIdPart1 == other.secondNaturalIdPart1) && (this.secondNaturalIdPart2 == other.secondNaturalIdPart2);
    }
}