英文:
Is there a way to describe unique sequence per each row in Spring Hibernate?
问题
我尝试过使用复合键，但有以下问题：
- 复合键不支持自动生成。
- @IdClass存在问题（Spring无法构造long类）。
- @EmbeddedId可行，但仍然存在第一问题。
基本上，我想要做的是，每一行（board link）都有唯一的序列，就像这样：
+---------+-----------+------------+
| post_id | thread_id | board_link |
+---------+-----------+------------+
| 1 | 1 | board_1 |
| 2 | 1 | board_1 |
| 3 | 1 | board_1 |
| 1 | 2 | board_2 |
| 2 | 2 | board_2 |
| 3 | 3 | board_2 |
+---------+-----------+------------+
我正在使用Spring Boot 2.2.6.RELEASE，PostgreSQL 12.3-2（9.6 testcontainers）和6.3.2 flyway-core。都是通过gradle构建。
英文:
I've tried using composite keys - but:
- Composite keys doesn't work with auto generation
- @IdClass is broken (long class couldn't be constructed by Spring)
- @EmbeddedId works but №1 issue is still there
Basically what i want to do, is make unique sequence per row (board link), like this:
+---------+-----------+------------+
| post_id | thread_id | board_link |
+---------+-----------+------------+
| 1 | 1 | board_1 |
| 2 | 1 | board_1 |
| 3 | 1 | board_1 |
| 1 | 2 | board_2 |
| 2 | 2 | board_2 |
| 3 | 3 | board_2 |
+---------+-----------+------------+
I'm using Spring Boot 2.2.6.RELEASE, PostgreSQL 12.3-2 (9.6 testcontainers) and 6.3.2 flyway-core. All through gradle.
答案1
得分: 1
你可以使用 GeneratedValue 注解，并将策略设置为 GenerationType.SEQUENCE
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
@Column(name = "id", updatable = false, nullable = false)
private Long id;
英文:
You can use the GeneratedValue annotation and set the strategy as GenerationType.SEQUENCE
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
@Column(name = "id", updatable = false, nullable = false)
private Long id;
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