使用 EntityManager NativeQuery 生成自增数并将数据插入 Oracle DB

Question

I am developing an ETL application using Spring. I have the data to be inserted in String type and want to load the data using entityManager.createNativeQuery(query).executeUpdate() I do not have any entity here as the ETL application can be used for any datasource.

To demonstrate the problem:

The source data can be any valid JSON like {name: "John", age: 31, city: "New York"}

The application itself generates the INSERT query from here like: INSERT INTO TABLE_NAME (Name, Age, City) values ('John',31,'New York')

I am using an @PersistenceContext EntityManager em to connect to Oracle 12c. Thus, running em.createNativeQuery(query).executeUpdate does the job for me.

However, when I try to use an own index within the target table, I am not able o figure out the correct method of doing so.

I tried using KeyHolder class, but it works with JdbcTemplate and not EntityManager

KeyHolder keyHolder = new GeneratedKeyHolder();

I am unable to use

em.getEntityManagerFactory().getPersistenceUnitUtil().getIdentifier(entity);

as I can't create an entity here.

What would be the correct mehtod of creating an own unique key here?

Answer 1

I recommend switching to JdbcTemplate since it doesn't look like you are using any of the features of JPA anyway.

If you insist on using the EntityManager , I think you'll have to select the sequence number first using SELECT my_seq.nextval FROM DUAL and then use that for the insert statement.