本文介绍了用于PostgreSQL的一个实体的多个Hibernate序列生成器的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我可以为一个实体使用多个序列生成器,如
@Id
@SequenceGenerator(name =
@GeneratedValue(strategy = GenerationType.SEQUENCE,generator =subscription_id_seq)
@Column(unique = true,nullable = false)
私人整数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;
解决方案
不,该生成器仅适用于标识符列。
确保使用脚本创建此序列(例如 hibernate.hbm2ddl.import_files $ b $ pre $
create sequence subscription_code_1_seq start 1 increment 7
然后用这样的映射:
@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,
可更新= false,
columnDefinition =BIGINT DEFAULT nextval('subscription_code_1_seq')
)
@Generated(GenerationTime.INSERT)
private Integer code;
Can I use Multiple sequence generators for one entity, like
@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;
解决方案
No you can not. The generator are applicable for identifier columns only.
Make sure you create this sequence with a script (e.g.
hibernate.hbm2ddl.import_files
):
create sequence subscription_code_1_seq start 1 increment 7
Then use a mapping like this:
@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;
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