Java 单个实体中多个外键的 Spring DATA JPA 示例
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时间：2020-08-14 12:14:24 来源:igfitidea点击:
Spring DATA JPA example for multiple foreign keys in a single entity
提问by user3560205
Below is my table design. can someone explain me how to configure my entity using spring data jpa?
下面是我的桌子设计。有人可以解释我如何使用 spring 数据 jpa 配置我的实体吗？
PARENT_TABLE(
id primary key,
name
)
SECOND_CHILD_TABLE(
id primary key,
second_child_name,
parent_id references id on parent_table,
first_child_id references id on first_child_table
)
FIRST_CHILD_TABLE(
id primary key,
first_child_name,
parent_id references id on parent_table
)
回答by shazin
If you are asking for JPA Mapping then should be as following.
如果您要求 JPA 映射，则应如下所示。
@Entity
@Table(name="parent_table")
public class Parent {
@Id
@Column(name="ID", nullable=false, unique=true)
// Require Generator config
private Long id;
@Column(name="NAME", nullable=false)
private String name;
}
@Entity
@Table(name="first_child_table")
public class FirstChild {
@Id
@Column(name="ID", nullable=false, unique=true)
// Require Generator config
private Long id;
@Column(name="FIRST_CHILD_NAME", nullable=false)
private String name;
@OneToOne
@JoinColumn(name="parent_id", referencedColumnName="ID")
private Parent parent;
}
@Entity
@Table(name="second_child_table")
public class SecondChild {
@Id
@Column(name="ID", nullable=false, unique=true)
// Require Generator config
private Long id;
@Column(name="SECOND_CHILD_NAME", nullable=false)
private String name;
@OneToOne
@JoinColumn(name="parent_id", referencedColumnName="ID")
private Parent parent;
@OneToOne
@JoinColumn(name="first_child_id", referencedColumnName="ID")
private FirstChild firstChild;
}
回答by paul
@Entity
@Table(name="parent_table")
public class Parent {
@Id
@Column(name="ID", nullable=false, unique=true)
// Require Generator config
private Long id;
@Column(name="NAME", nullable=false)
private String name;
@OneToMany(orphanRemoval = true, cascade = {CascadeType.ALL}, fetch = FetchType.LAZY)
@JoinColumn(name = "candidacy_id", nullable = false)
@Getter
@Setter
private List<FirstChild> firstChild = new ArrayList<>();
@OneToMany(orphanRemoval = true, cascade = {CascadeType.ALL}, fetch = FetchType.LAZY)
@JoinColumn(name = "candidacy_id", nullable = false)
@Getter
@Setter
private List<SecondChild> secondChild = new ArrayList<>();
}
@Entity
@Table(name="first_child_table")
public class FirstChild {
@Id
@Column(name="ID", nullable=false, unique=true)
// Require Generator config
private Long id;
@Column(name="FIRST_CHILD_NAME", nullable=false)
private String name;
@ManyToOne
@JoinColumn(name="parent_id", referencedColumnName="ID")
private Parent parent;
}
@Entity
@Table(name="second_child_table")
public class SecondChild {
@Id
@Column(name="ID", nullable=false, unique=true)
// Require Generator config
private Long id;
@Column(name="SECOND_CHILD_NAME", nullable=false)
private String name;
@ManyToOne
@JoinColumn(name="parent_id", referencedColumnName="ID")
private Parent parent;
}
And for the repository
对于存储库
@Repository
public interface ParentRepository extends CrudRepository<Parent, Integer> {
}
