JPA物體外鍵是來自其他物體的主鍵-有解無憂

如果這篇文章標題不能理解，我很抱歉

我在 Oracle 資料庫中有幾個表，我想在 Spring Boot JPA 中生成每個物體。

這是我的一塊：

CREATE TABLE T1 (
   C1 NUMBER(4) NOT NULL,
   C2 NUMBER(5) NOT NULL,
   C3 NUMBER(2) NOT NULL,
   C4 NUMBER(9) NOT NULL,
   C5 VARCHAR2(10 CHAR) NOT NULL,
   CONSTRAINT PK_T1 PRIMARY KEY (C1,C2,C3,C4)
);

CREATE TABLE T2 (
   C1 NUMBER(4) NOT NULL,
   C2 NUMBER(5) NOT NULL,
   C3 NUMBER(2) NOT NULL,
   C4 NUMBER(9) NOT NULL,
   C5 NUMBER(6) NOT NULL,
   C6 NUMBER(3) NOT NULL,
   C7 VARCHAR2(10 CHAR) NOT NULL,
   C8 VARCHAR2(20 CHAR) NOT NULL,
   CONSTRAINT PK_T2 PRIMARY KEY (C1,C2,C3,C4,C5,C6),
   CONSTRAINT FK_T2_T1 FOREIGN KEY (C1,C2,C3,C4) REFERENCES T1
);

我需要將這兩個表映射到 JPA 物體，但我不知道如何映射它們。

這些是 Java 中的物體類：

import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.Table;
import lombok.Data;
@Entity
@Table(name = "T1")
@Data
public class T1Bean implements Serializable {
   @EmbeddedId
   private T1PK pk;
   @Basic
   @Column(name = "C5", nullable = false)
   private String c5;
}
------------------
import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Embeddable;
import lombok.Data;
@Data
@Embeddable
public class T1PK implements Serializable {
   @Basic
   @Column(name = "C1", nullable = false)
   private int c1;
   @Basic
   @Column(name = "C2", nullable = false)
   private int c2;
   @Basic
   @Column(name = "C3", nullable = false)
   private int c3;
   @Basic
   @Column(name = "C4", nullable = false)
   private long c4;
}
------------------
import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import lombok.Data;
@Entity
@Table(name = "T2")
@Data
public class T2Bean implements Serializable {
   @EmbeddedId
   private T2PK pk;
   @Basic
   @Column(name = "C7", nullable = false)
   private String c7;
   @Basic
   @Column(name = "C8", nullable = false)
   private String c8;
   @OneToOne
   private T1Bean t1Bean;
}
------------------
import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Embeddable;
import lombok.Data;
@Data
@Embeddable
public class T2PK implements Serializable {
   @Basic
   @Column(name = "C1", nullable = false)
   private int c1;
   @Basic
   @Column(name = "C2", nullable = false)
   private int c2;
   @Basic
   @Column(name = "C3", nullable = false)
   private int c3;
   @Basic
   @Column(name = "C4", nullable = false)
   private long c4;
   @Basic
   @Column(name = "C5", nullable = false)
   private int c5;
   @Basic
   @Column(name = "C6", nullable = false)
   private int c6;
}

T2Bean 物體中缺少哪個注釋以使每個物體之間的映射看起來不錯？

我只放了@OneToOne 注釋，但我不知道是否正確。

uj5u.com熱心網友回復：

首先你只需要映射兩個類 T1 和 T2 這些類被認為是 Bean 或模塊或物體

物體T1

@Entity
@Table(name = "T1")
@Data
public class T1 implements Serializable {
@EmbeddedId
private <type> c1;
private <type> c2;
private <type> c3;
private <type> c4;

private T2 t2;
/* getters & setters */
@Column(name = "C1", nullable = false)
public String getC1(){
    return c1;
}

public void setC1(c1){
    this.c1 = c1;
}

// .... All other classes are the same

@OneToOne(fetch = FetchType.EAGER, targetEntity = T2.class)
public T2 getT2(){
    return t2;
}

public void setT2(t2){
    this.t2 = t2;
}

物體T2

@Entity
@Table(name = "T2")
@Data
public class T2 implements Serializable {
@EmbeddedId
private <type> c1;
private <type> c2;
private <type> c3;
private <type> c4;
private <type> c5;
private <type> c6;
private <type> c7;
private <type> c8;

private T1 t1;
/* getters & setters */
@Column(name = "C1", nullable = false)
public String getC1(){
    return c1;
}

public void setC1(c1){
    this.c1 = c1;
}

//Foreigin key 
@OneToOne(fetch = FetchType.EAGER, targetEntity = T1.class)
@JoinColumn(name ="c1", nullable = false)
public T1 getT1(){
    return t1;
}

public void setT1(t1){
    this.t1 = t1;
}

uj5u.com熱心網友回復：

感謝@chris評論。

我找到了 T2Bean 物體的解決方案，如下所示：

@Entity
@Table(name = "T2")
@Data
public class T2Bean implements Serializable {
   @EmbeddedId
   private T2PK pk;
   @Basic
   @Column(name = "C7", nullable = false)
   private String c7;
   @Basic
   @Column(name = "C8", nullable = false)
   private String c8;
   @ManyToOne(fetch = FetchType.EAGER)
   @JoinColumns({
         @JoinColumn(name = "c1",referencedColumnName = "c1",insertable = false,updatable = false),
         @JoinColumn(name = "c2",referencedColumnName = "c2",insertable = false,updatable = false),
         @JoinColumn(name = "c3",referencedColumnName = "c3",insertable = false,updatable = false),
         @JoinColumn(name = "c4",referencedColumnName = "c4",insertable = false,updatable = false),
   })
   private T1Bean t1Bean;
}

以及帶有注釋@PrimaryKeyJoinColumn 的T1 的@Embeddable。

@Data
@Embeddable
@PrimaryKeyJoinColumn
public class T1PK implements Serializable {
   @Basic
   @Column(name = "C1", nullable = false)
   private int c1;
   @Basic
   @Column(name = "C2", nullable = false)
   private int c2;
   @Basic
   @Column(name = "C3", nullable = false)
   private int c3;
   @Basic
   @Column(name = "C4", nullable = false)
   private long c4;
}

使用該物體，第二個請求不起作用：

請求 1：

{
    "pk": {
        "c1": 1,
        "c2": 2,
        "c3": 3,
        "c4": 998755544548
    },
    "c5": "John"
}

請求 2：

{
    "pk": {
        "c1": 1,
        "c2": 2,
        "c3": 5,
        "c4": 998755544548,
        "c5": 55,
        "c6": 15
    },
    "c7": "Simon",
    "c8": "system"
}

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標籤：爪哇甲骨文弹簧靴 jpa 奥姆

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