java - ORA-02291 : integrity constraint violated - parent key not found When trying to insert null in foreign key

Question

我有一个要求，我必须向同一个表中的特定列添加外键约束。例如，我有一个表 PROJECT，它有一个主键列“id”和另一列“dependency_project_id”，它是引用“id”列的外键。

我更改了表格并添加了如下约束:更改表项目添加约束 FK_DEPENDENCY_PROJECT_ID 外键 (DEPENDENCY_PROJECT_ID) 引用项目 (ID)；

但是，我的第二个要求是，“dependency_project_id”列在某些情况下可以为空。但是，如果我尝试在 dependency_project_id 列中插入 null，则会收到错误“ORA-02291:违反完整性约束 - 未找到父键”。

请注意，我正在使用 JPA 将数据保存到数据库中。但是，如果我直接在数据库中的 dependency_project_id 列中插入 null，则可以毫无问题地执行此操作。

这是我的实体。

package com.oracle.estimationtool.model;
import java.util.List;
import javax.json.bind.annotation.JsonbTransient;
import javax.persistence.Access;
import javax.persistence.AccessType;
import javax.persistence.Basic;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.Lob;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.Size;

@Entity(name = "Project")
@Table(name = "PROJECT")
@Access(value = AccessType.FIELD)
@SequenceGenerator(name = "ProjectSeq", sequenceName = "PROJECT_SEQ", allocationSize = 50)
@NamedQuery(name = "Project.findProject", query = "SELECT p from Project p where p.id = :id")
public class Project extends BaseEntity {
    @Id
    @GeneratedValue(generator = "ProjectSeq", strategy = GenerationType.SEQUENCE)
    private Integer id;
    @OneToMany
    @JoinColumn(name = "PROJECT_ID")
    private  List<SolutionComponentEstimate> solutionComponentEstimates;
    @Column(columnDefinition = "CLOB NULL", name = "BUSINESS_EVENTS", nullable = true)
    @Lob
    @Basic(optional = true)
    private List<BusinessEvent>businessEvents;
    @Column(nullable = true, precision = 10, scale = 4)
    @Basic(optional = true)
    private Double duration;
    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
    @JoinColumn(name = "PROJECT_ID")
    private List<SCVersionProject> scvproject;
    @Column(name = "NAME", length = 255, nullable = false)
    @Basic(optional = false)
    @Size(max = 255)
    @NotBlank
    private String name;
    @Column(name = "DEPENDENCY_PROJECT_ID", nullable = true)
    @Basic(optional = true)
    private int dependencyProjectId;
    @Column(name = "DEPENDENCY_START", nullable = true)
    @Basic(optional = true)
    private boolean dependencyStart;
    @Column(name = "DEPENDENCY_DELTA", nullable = true)
    @Basic(optional = true)
    private int dependencyDelta;
    @ManyToOne
    @JoinColumn(name = "ROADMAP_ID")
    @JsonbTransient
    private Roadmap roadmap;

    public Project() {
    }

    public Project(List<SolutionComponentEstimate> solutionComponentEstimates, List<BusinessEvent> businessEvents,
            Double duration, String name) {
        this.solutionComponentEstimates = solutionComponentEstimates;
        this.businessEvents = businessEvents;
        this.duration = duration;
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public List<SolutionComponentEstimate> getSolutionComponentEstimates() {
        return solutionComponentEstimates;
    }

    public void setSolutionComponentEstimates(List<SolutionComponentEstimate> solutionComponentEstimates) {
        this.solutionComponentEstimates = solutionComponentEstimates;
    }

    public List<BusinessEvent> getBusinessEvents() {
        return businessEvents;
    }

    public void setBusinessEvents(List<BusinessEvent> businessEvents) {
        this.businessEvents = businessEvents;
    }

    public Double getDuration() {
        return duration;
    }

    public void setDuration(Double duration) {
        this.duration = duration;
    }

    public List<SCVersionProject> getScvproject() {
        return scvproject;
    }

    public void setScvproject(List<SCVersionProject> scvproject) {
        this.scvproject = scvproject;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getDependencyProjectId() {
        return dependencyProjectId;
    }

    public void setDependencyProjectId(int dependencyProjectId) {
        this.dependencyProjectId = dependencyProjectId;
    }

    public boolean isDependencyStart() {
        return dependencyStart;
    }

    public void setDependencyStart(boolean dependencyStart) {
        this.dependencyStart = dependencyStart;
    }

    public int getDependencyDelta() {
        return dependencyDelta;
    }

    public void setDependencyDelta(int dependencyDelta) {
        this.dependencyDelta = dependencyDelta;
    }

    public Roadmap getRoadmap() {
        return roadmap;
    }

    public void setRoadmap(Roadmap roadmap) {
        this.roadmap = roadmap;
    }

}

我是 JPA 新手。我是否缺少任何内容或有任何解决方法？非常感谢任何帮助。

Answer 1

您应该将 DEPENDENCY_PROJECT_ID 映射到 Integer 而不是 int。int 不能有空值。如果没有设置，则值为 0，因此违反约束。