我与复合键有很多关系。现在我想从连接实体类中删除一个项目,该项目是数据库中的一行。我怎样才能做到这一点?
第1节
@OneToMany(cascade=CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "tag", , orphanRemoval = true)
private List<TagDefinitionProject> tagProjects = new ArrayList<TagDefinitionProject>();
第2侧
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "project", , orphanRemoval = true)
private List<TagDefinitionProject> tagProjects = new ArrayList<TagDefinitionProject>();
加入课程:
@Id
@JoinColumn(name = "id_tag", referencedColumnName = "id")
@ManyToOne(optional = false)
@JsonBackReference
private Tag tag;
@Id
@JoinColumn(name = "id_project", referencedColumnName = "id_project")
@ManyToOne(optional = false,fetch = FetchType.EAGER)
private Project project;
PK课程:
@Id
@Column(name = "id_tag")
private Integer tag;
@Id
@Column(name = "id_project")
private Integer project;
在我的服务层代码中,我正在尝试这样做,但它不起作用。
TagDefinitionProject t = tagDao.findByTagAndProject(i,j);
tdpDao.remove(t);