JPA Spring Data 常用寶典
@annotation
@Transient
```java= @Transient @JsonIgnore public static String getUidByInfo(UidArgs args) { return null; }
不會當成欄位值
## 常見問題
### No EntityManager with actual transaction available for current thread - cannot reliably process 'remove' call
會遇到這個問題,就是在一個Transactional有新增又有刪除的情況發生,最簡的的辦法就是在 Dao 加上以下 Annotation
```cmake=
@Transactional
@Modifying
ex:
```java=
@Repository
public interface RunLogDao extends CrudRepository
List<RunLog> findByRunFlowUidOrderByCreateAtAsc(String uid);
@Transactional
@Modifying
List<RunLog> deleteByCreateAtBefore(Date date);
} ```