PostgreSQL的一个实体的多个Hibernate序列生成器

Question

我可以为一个实体使用多个序列生成器吗？

@Id
@SequenceGenerator(name=”subscription_id_seq”,sequenceName=”subscription_id_seq”, allocationSize=7)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator=”subscription_id_seq”)
@Column(unique=true, nullable=false)
private Integer id

@Column(name="code", nullable=false, unique=true )
@SequenceGenerator(name="subscription_code_1_seq",sequenceName="subscription_code_1_seq", allocationSize=7)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="subscription_code_1_seq")
private Integer code;

Answer 1

你不能。该生成器仅适用于标识符列。

确保使用脚本（例如hibernate.hbm2ddl.import_files）创建此序列：

create sequence subscription_code_1_seq start 1 increment 7

然后使用如下映射：

@Id
@SequenceGenerator(
        name="subscription_id_seq",
        sequenceName="subscription_id_seq",
        allocationSize=7
)
@GeneratedValue(
        strategy=GenerationType.SEQUENCE,
        generator="subscription_id_seq"
)
@Column(unique=true, nullable=false)
private Integer id;

@Column(
        name="code",
        nullable=false,
        unique=true,
        insertable = false,
        updatable = false,
        columnDefinition = "BIGINT DEFAULT nextval('subscription_code_1_seq')"
)
@Generated(GenerationTime.INSERT)
private Integer code;