Question

我知道truncate不受支持，因此我执行了Delete from table - 这项工作非常好但是连接表不会以这种方式清理。例如：

Delete from Product;
Delete from Service;

两个空，表service_product仍然填充。有没有机会在没有原始sql的情况下清理我的连接表？

示例实体

public class Service implements Serializable {
    private static final long serialVersionUID = 4520872456865907866L;
    // seam-gen attributes (you should probably edit these)

    @EmbeddedId
    private ServiceId id;

    @Length(max = 255)
    private String servicename;

    @Column(columnDefinition = "text")
    private String highlightsText;
    @Column(columnDefinition = "text")
    private String detailsText;
    @Column(columnDefinition = "text")
    private String productText;
    @Column(columnDefinition = "text")
    private String dataText;

    @ManyToMany(mappedBy = "services")
    private Set<Machine> machines;

    @OneToMany(targetEntity = ServiceDownload.class, cascade = { CascadeType.ALL }, fetch = FetchType.LAZY)
    private List<ServiceDownload> serviceDownloads;

    @OneToMany(targetEntity = ProductSpecial.class, cascade = { CascadeType.ALL })
    private List<ProductSpecial> productSpecials;

    @OneToOne(cascade = { CascadeType.ALL })
    private ServicePicture servicePicture;
...
}

Answer 1

您必须获取完整表格（FROM Product），迭代实体并使用session.delete(..)
DELETE不会触发级联
truncate

Answer 2

您应该添加@OnDelete（action = OnDeleteAction.CASCADE）注释。所以，如果您正在使用Hibernate，请尝试：

@OneToMany(targetEntity = ServiceDownload.class, cascade = { CascadeType.ALL }, fetch = FetchType.LAZY)
@OnDelete(action=OnDeleteAction.CASCADE)
private List<ServiceDownload> serviceDownloads;

有关示例和文档，请参阅http://docs.jboss.org/hibernate/stable/annotations/reference/en/html/entity.html。

JPA空表和连接表

2 个答案: