New Table创建了更新现有表的界面。 OneToMany与CompositeKey映射，springboot，休眠

Question

我的架构中有两个表，它们之间具有一对多的关系。

unit and unit_bridge

单位有2列id和name

unit_bridge有两列，unit_master_id和unit_slave_id。它们两者共同构成一个composite key。这里unit_slave_id是单元中id列的外键。

当我收到POST请求时，正在数据库中创建一个名为unit_child_units的新表。并且unit_bridge的unit_slave_id列值被更新。尽管unit_master_id的值在unit_bridge表中是正确的，但它对应的unit_slave_id映射是错误的。

我不需要新表，而是要更新unit_bridge表，因为我收到了用户对unit表的POST请求。

这是我的json请求，

{
"name" : "john doe",
"childUnits" : [
               {

               "unitBridgeId" :{
                  "unit_master_id" : 4
                }
             }
          ]

}

这是我的模特。

Unit.java

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Transient;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;

@Entity
@Table(name="unit")
@JsonInclude(Include.NON_NULL)
public class Unit implements Serializable{

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;
    private String name;

    @Transient
    private int parent_id;

    @OneToMany(cascade=CascadeType.ALL)
    @PrimaryKeyJoinColumn
    private Set<UnitBridge> childUnits = new HashSet<UnitBridge>();

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public int getParent_id() {
        return parent_id;
    }

    public void setParent_id(int parent_id) {
        this.parent_id = parent_id;
    }

    public Set<UnitBridge> getChildUnits() {
        return childUnits;
    }

    public void setChildUnits(Set<UnitBridge> childUnits) {
        this.childUnits = childUnits;
    }

    @Override
    public String toString() {
        return "Unit [id=" + id + ", name=" + name + ", parent_id=" + parent_id + ", childUnits=" + childUnits + "]";
    }

}

UnitBridge.java

import java.io.Serializable;

import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.Table;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;

@Entity
@Table(name="unit_bridge")
@JsonInclude(Include.NON_NULL)
public class UnitBridge implements Serializable{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    @EmbeddedId
    private UnitBridgeId unitBridgeId;

    @Override
    public String toString() {
        return "UnitBridge [unitBridgeId=" + unitBridgeId + "]";
    }

    public UnitBridgeId getUnitBridgeId() {
        return unitBridgeId;
    }

    public void setUnitBridgeId(UnitBridgeId unitBridgeId) {
        this.unitBridgeId = unitBridgeId;
    }


    public int getUnit_master_id() {
        return unitBridgeId.getUnit_master_id();
    }

    public int getUnit_slave_id() {
        return unitBridgeId.getUnit_slave_id();
    }

    public void setUnit_master_id(int unit_master_id) {
        unitBridgeId.setUnit_master_id(unit_master_id);
    }
    public void setUnit_slave_id(int unit_slave_id) {
        unitBridgeId.setUnit_slave_id(unit_slave_id);
    }
}

UnitBridgeId.java

import java.io.Serializable;

import javax.persistence.Embeddable;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;

@Embeddable
public class UnitBridgeId implements Serializable {


    private static final long serialVersionUID = 1L;

    private int unit_master_id;

    private int unit_slave_id;

    public UnitBridgeId() {

    }

    public UnitBridgeId(int unit_master_id, int unit_slave_id) {
        this.unit_master_id = unit_master_id;
        this.unit_slave_id=unit_slave_id;
    }

    public int getUnit_master_id() {
        return unit_master_id;
    }

    public void setUnit_master_id(int unit_master_id) {
        this.unit_master_id = unit_master_id;
    }

    public int getUnit_slave_id() {
        return unit_slave_id;
    }

    public void setUnit_slave_id(int unit_slave_id) {
        this.unit_slave_id = unit_slave_id;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + unit_master_id;
        result = prime * result + unit_slave_id;
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        UnitBridgeId other = (UnitBridgeId) obj;
        if (unit_master_id != other.unit_master_id)
            return false;
        if (unit_slave_id != other.unit_slave_id)
            return false;
        return true;
    }

    @Override
    public String toString() {
        return "UnitBridgeId [unit_master_id=" + unit_master_id + ", unit_slave_id=" + unit_slave_id + "]";
    }

}

Answer 1

UnitBridge中的ManyToOne关系，而不是

Unit中的OneToMany，这样就不需要映射表。

@Table(name="unit")
public class Unit implements Serializable{

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;
    private String name;

    @Transient
    private int parent_id;

    //getters and setters
}

@Entity
@Table(name="unit_bridge")
public class UnitBridge implements Serializable{
    private static final long serialVersionUID = 1L;

    @EmbeddedId
    private UnitBridgeId unitBridgeId;

    @ManyToOne
    private Unit unit;

    //getters and setters
}