Question

我正在尝试使用OneToOne映射将数据保存在两个表中。我已经关注了 this，this，this，this以及更多在线资源来完成此任务，但它正在投掷

ORA-02291: integrity constraint (TableName.TEST_ID) violated - parent key not found

创建列TESTID为外键的表。在父表中TESTID是主键。主键是使用序列生成器生成的

CREATE TABLE EW_TEST_REFTABLE (
  ID int NOT NULL PRIMARY KEY,
  TESTNAME VARCHAR2(20) NOT NULL,
  TESTID int,
  CONSTRAINT test_id FOREIGN KEY(TESTID)
  REFERENCES EW_TESTDATA(TESTID)
);

Ew_testdataEntity.java（父表的实体类）

@Entity
@Table(name = "EW_TESTDATA")
public class Ew_testdata {
    @Id
    @SequenceGenerator(name = "sube_seq",
            sequenceName = "EW_TESTDATA_SEQ",
            allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sube_seq")

    @Column(name = "TESTID")
    private int testid;

    @Column(name = "TESTNAME")
    private String testname;

    // Ew_test_reftable  is another entity class.In that table the column
    // TESTID (foreign key) must be same as the primary key of this 
    // entity/table(EW_TESTDATA)
    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "TESTID",unique = true)
    private Ew_test_reftable ewtestreftable;

       //Constructor
       // getter & setter
    }

Ew_test_reftable.java

@Entity
@Table(name = "EW_TEST_REFTABLE")
public class Ew_test_reftable {

    @Id
    @SequenceGenerator(name = "subf_seq", sequenceName = "EW_REF_SEQ", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "subf_seq")
    @Column(name = "ID")
    private int id;

    @Column(name = "TESTNAME")
    private String testname;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "TESTID")
    private int testid;
    //Constructor,getter & setter
}

使用Jpa

保存数据的服务

@Override
    public Ew_testdata ew_testdata(String name) {

        Ew_test_reftable ew_test_reftable = new Ew_test_reftable();
        ew_test_reftable.setTestname("test");
        Ew_testdata ew_testdata = new Ew_testdata();
        ew_testdata.setTestname(name);
        ew_testdata.setEwtestreftable(ew_test_reftable);
        iew_tEst.ewTestdata(ew_testdata);
        return null;
    }

问题似乎与SO中描述的其他几个问题类似，但我仍然无法弄清楚我在哪里犯错误

Answer 1

你的实体和表格结构看起来相反，这让人很难理解。

现在，提到例外

ORA-02291: integrity constraint (TableName.TEST_ID) violated - parent key not found

这意味着，在向子表添加新行时，您没有在子表中引用父ID。

在Ew_test_reftable课程中，您有

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "TESTID")
private int testid;

如果我理解正确，testid是EW_TEST_REFTABLE中的外键，那你为什么要使用GenerationType.IDENTITY？这将创建新的序列ID，可能与父键不匹配，导致错误/异常。

根据我对您的设计的理解，

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "TESTID")
private int testid;

更改为

@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "TESTID",unique = true)
private Ew_testdata ew_testdata;

与上述代码类似，应从Ew_testdata实体中删除（此处可能会略有变化）

无法使用OneToOne映射保存数据

1 个答案: