使用Spring Data JPA，QueryDSL更新一堆记录

Question

I'm refactoring a code base to get rid of SQL statements and primitive access and modernize with Spring Data JPA (backed by hibernate). I do use QueryDSL in the project for other uses.

I have a scenario where the user can "mass update" a ton of records, and select some values that they want to update. In the old way, the code manually built the update statement with an IN statement for the where for the PK (which items to update), and also manually built the SET clauses (where the options in SET clauses can vary depending on what the user wants to update).

In looking at QueryDSL documentation, it shows that it supports what I want to do. http://www.querydsl.com/static/querydsl/4.1.2/reference/html_single/#d0e399

I tried looking for a way to do this with Spring Data JPA, and haven't had any luck. Is there a repostitory interface I'm missing, or another library that is required....or would I need to autowire a queryFactory into a custom repository implementation and very literally implement the code in the QueryDSL example?

Answer 1

You can either write a custom method or use @Query annotation.

For custom method;

public interface RecordRepository extends RecordRepositoryCustom, 
                                          CrudRepository<Record, Long> 
{
}

public interface RecordRepositoryCustom {
      // Custom method
      void massUpdateRecords(long... ids);
}

public class RecordRepositoryImpl implements RecordRepositoryCustom {
      @Override
      public void massUpdateRecords(long... ids) {
           //implement using em or querydsl
      }
}

For @Query annotation;

public interface RecordRepository extends CrudRepository<Record, Long> 
{
      @Query("update records set someColumn=someValue where id in :ids")
      void massUpdateRecords(@Param("ids") long... ids);
}

There is also @NamedQuery option if you want your model class to be reusable with custom methods;

@Entity
@NamedQuery(name = "Record.massUpdateRecords", query = "update records set someColumn=someValue where id in :ids")
@Table(name = "records")
public class Record {   
      @Id
      @GeneratedValue(strategy = GenerationType.AUTO)
      private Long id;
      //rest of the entity...
}

public interface RecordRepository extends CrudRepository<Record, Long> 
{
      //this will use the namedquery
      void massUpdateRecords(@Param("ids") long... ids);
}

Check repositories.custom-implementations , jpa.query-methods.at-query and jpa.query-methods.named-queries at spring data reference document for more info.

Answer 2

This question is quite interesting for me because I was solving this very problem in my current project with the same technology stack mentioned in your question. Particularly we were interested in the second part of your question:

where the options in SET clauses can vary depending on what the user wants to update

I do understand this is the answer you probably do not want to get but we did not find anything out there :( Spring data is quite cumbersome for update operations especially when it comes to their flexibility.

After I saw your question I tried to look up something new for spring and QueryDSL integration (you know, maybe something was released during past months) but nothing was released.

The only thing that brought me quite close is .flush in entity manager meaning you could follow the following scenario:

1. Get ids of entities you want to update
2. Retrieve all entities by these ids ( first actual query to db )
3. Modify them in any way you want
4. Call entityManager.flush resulting N separate updates to database .

This approach results N+1 actual queries to database where N = number of ids needed to be updated. Moreover you are moving the data back and forth which is actually not good too.

I would advise to

autowire a queryFactory into a custom repository implementation

Also, have a look into spring data and querydsl example . However you will find only lookup examples.

Hope my pessimistic answer helps :)