Question

我有以下实体，当删除ServiceRegistration记录时，我必须删除ServiceRegistration和ServiceChannels条目。但现在，如果我删除了serviceregistration中的记录，它将删除通道中的记录，即元数据表。

ServiceRegistration.Java

@OneToMany(cascade=CascadeType.ALL,fetch = FetchType.EAGER)
@JoinTable(name = "ServiceChannel", joinColumns = {
 @JoinColumn(name="serviceid", unique = true) 
 },
 inverseJoinColumns = {
 @JoinColumn(name="channelid")
 }
 )

 private List<Channels> channelsInvolved;

     public List<Channels> getChannelsInvolved() {
    return channelsInvolved;
  }

public void setChannelsInvolved(List<Channels> channelsInvolved) {
    this.channelsInvolved = channelsInvolved;
  }

ServiceChannels.java

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column private int servicechannelid;    

@ManyToOne
@JoinColumn(name = "serviceid")
private ServiceRegistration serviceRegistration;

@ManyToOne
@JoinColumn(name = "channelid")
private Channels channels;

Channels.java＆gt;＆gt;包含元数据

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column private int channelid;
@Column private String channelname;

@Override
    public boolean equals(final Object obj) {
        if (obj instanceof Channels) {
            final Channels other = (Channels) obj;
            if (other.getChannelid() == getChannelid()) {
                return true;
            }
        } 
        return false;
    }

请帮我看看如何在这个实体关系中进行级联删除。

Answer 1

首先，如果您不希望在删除ServiceRegistration时删除频道，则应执行以下操作：

@OneToMany(fetch = FetchType.EAGER)
@JoinTable(name = "ServiceChannel", joinColumns = {
 @JoinColumn(name="serviceid", unique = true) 
 },
 inverseJoinColumns = {
 @JoinColumn(name="channelid")
 }
 )

 private List<Channels> channelsInvolved;

在您的服务注册中（禁用级联）。

此外，如果要在删除ServiceRegistration时删除ServiceChannel，则必须在ServiceRegistration端配置关系：

@OneToMany(mappedBy="serviceRegistration", cascade=CascadeType.REMOVE) // Edited to specify the owning side of the relationship
private List<ServiceChannel> serviceChannels;

Spring MVC 3 Hibernate JPA Annotations onetomany和manytoone relationship cascade delete

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