Postgresql 定义从一个实体到另一个实体的一对多映射时遇到的问题

假设我有两个表T1和T2

t1id is Primary Key (PK) in table T1 . T1 references T2 via t2id which is Foreign Key(FK) T1 to T2 is one to many relationship Schemas : -------------------------------------------------------- T1 ( t1id (PK) , name , t2id(FK)) T2 ( t2id(PK) , author) ------------------------------------------------------- t1id是表T1中的主键（PK）。 T1通过作为外键（FK）的t2id引用T2 T1到T2是一对多关系 模式： -------------------------------------------------------- T1（t1id（主键）、名称、t2id（FK）） T2（t2id（主键），作者） -------------------------------------------------------

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有人能帮我定义上述需求的enity类吗？

您可以像下面那样编写实体类

@Entity
@Table(name = "T1")
public class T1Entity implements Serializable {

@Id
@Column(name="t1id")
@SequenceGenerator(name = "t1_seq", sequenceName = "t1_seq", allocationSize = 1)
@GeneratedValue(generator = "t1_seq", strategy = GenerationType.SEQUENCE)
private Long t1id;

@ManyToOne(fetch = FetchType.EAGER, targetEntity = T2Entity.class)
@JoinColumn(name = "t2id", referencedColumnName = "t2id")
private T2Entity t2;


//getter and setter    
}

你的T2实体可以写成

@Entity
@Table(name = "T2")
public class T2Entity implements Serializable {

@Id
@Column(name="t2id")
@SequenceGenerator(name = "t2_seq", sequenceName = "t2_seq", allocationSize = 1)
@GeneratedValue(generator = "t2_seq", strategy = GenerationType.SEQUENCE)
private Long t2id;

//other columns

//getter and setter    
}

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如果需要，可以在t1和t2实体之间添加双向关系。如果你需要这样的关系，一定要告诉我。