java - 将列表存储在表列中

Question

我有表的表现和时间。一场演出可以在特定时间进行多次。一对多关系。

@Entity
@Table(name = "performance_type")
@Data
public class PerformanceType {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(nullable = false, unique = true)
    private Integer performanceTypeId;
    @Column(length=127)
    private String performOptions;
}

和

@Entity
@Table(name = "performance")
@Data
public class Performance {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(nullable = false, unique = true)
    private Integer performanceId;

    @OneToMany(mappedBy = "performance")
    private List<Hours> performanceHours = new ArrayList<>();
}

在数据库 hibernate 中创建表 hours，其 PerformanceId 只有一个值。我如何插入同时播放 id 1,4,7 的表演的列表值。我需要额外的表hours_performance来存储hourId和perfomanceId吗？

Answer 1

由于您想要实现的关系是(根据我的理解)多对多，因此您确实需要第三个表将时间映射到关系。 Here is a very good example.您需要设置第三个表，并使用两个外键连接到要连接的两个表。

@Entity
@Table(name = "performance")
@Data
public class Performance {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(nullable = false, unique = true)
    private Integer performanceId;

    @ManyToMany
    @JoinTable(
        name = "hours_performance", 
        joinColumns = { @JoinColumn(name = "performance_id") }, 
        inverseJoinColumns = { @JoinColumn(name = "hour_id") }
    )
    private List<Hours> performanceHours = new ArrayList<>();
}

@Entity
@Table(name = "hours")
@Data
public class Hours {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(nullable = false, unique = true)
    private Integer hourId;
    ZonedDateTime time;

    @ManyToMany(mappedBy = "performanceHours")
    private List<Performance> performances;
}