oracle通过sequence定义触发器支持id的自增

sequence：s_author_id，从1开始步幅是1，最大值是999999999

-- Create sequence 
create sequence S_AUTHOR_ID
minvalue 1
maxvalue 999999999
start with 1
increment by 1
cache 20;

触发器：trg_authors 

create or replace trigger trg_authors before insert on reader_resource_author for each row
begin
select s_author_id.nextval into :new.author_id from dual;
end;

java代码entity：

@Entity
@javax.persistence.SequenceGenerator(
        name = "authorid",
        sequenceName="s_author_id"
)
@Table(name = "reader_resource_author")
public class ResourceAuthor extends PersistentObject{

        @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE,generator="authorid")
    @Column(name = "author_id")
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
}