Update single field using spring data jpa

问题

I'm using spring-data's repositories - very convenient thing but I faced an issue. I easily can update whole entity but I believe it's pointless when I need to update only a single field:

@Entity
@Table(schema = "processors", name = "ear_attachment")
public class EARAttachment {

    private Long id;
    private String originalName;
    private String uniqueName;//yyyy-mm-dd-GUID-originalName
    private long size;
    private EARAttachmentStatus status;

to update I just call method save. In log I see the followwing:

batching 1 statements: 1: update processors.ear_attachment set message_id=100, 
original_name='40022530424.dat', 
size=506, 
status=2,
unique_name='2014-12-16-8cf74a74-e7f3-40d8-a1fb-393c2a806847-40022530424.dat'
where id=1

I would like to see some thing like this:

batching 1 statements: 1: update processors.ear_attachment set status=2 where id=1

Spring's repositories have a lot of facilities to select something using name conventions, maybe there is something similar for update like updateForStatus(int status);

回答1:

You can try something like this on your repository interface:

@Modifying
@Query("update EARAttachment ear set ear.status = ?1 where ear.id = ?2")
int setStatusForEARAttachment(Integer status, Long id);

You can also use named params, like this:

@Modifying
@Query("update EARAttachment ear set ear.status = :status where ear.id = :id")
int setStatusForEARAttachment(@Param("status") Integer status, @Param("id") Long id);

The int return value is the number of rows that where updated. You may also use void return.

See more in reference documentation.

回答2:

Hibernate offers the @DynamicUpdate annotation. All we need to do is to add this annotation at the entity level:

@Entity(name = "EARAttachment ")
@Table(name = "EARAttachment ")
@DynamicUpdate
public class EARAttachment {
    //Code omitted for brevity
}

Now, when you use EARAttachment.setStatus(value) and executing "CrudRepository" save(S entity), it will update only the particular field. e.g. the following UPDATE statement is executed:

UPDATE EARAttachment 
SET    status = 12,
WHERE  id = 1

来源：https://stackoverflow.com/questions/29202277/update-single-field-using-spring-data-jpa

标签

java

Spring

spring-data

updates

spring-data-jpa