PostgreSQL JDBC Null String taken as a bytea

Question

If entity.getHistory() is null following code snippet:

(getEntityManager() returns spring injected EntityManager, database field history type is: text or varchar2(20

Answer 1

Since you're calling setParameter(int,Object) with a null value, at a guess the entity manager has no idea which persistence type to use to bind the parameter. Istr Hibernate having a predilection for using SerializableType, which would equate to a bytea.

Can you use the setParameter method that takes a Parameter object instead, so you can specify the type? I haven't really used JPA, so can't give a detailed pointer.

(IMHO this is your just desserts for abusing EntityManager's native-sql query interface to do inserts, rather than actually mapping the entity, or just dropping through to JDBC)

Answer 2

Had this issue in my springboot application, with postgres and hibernate. I needed to supply date from/to parameters, with possible nulls in every combination.

Excerpt of the query :

   ...
        WHERE  f.idf = :idCat
        AND f.supplier = TRUE
        AND COALESCE (pc.datefrom, CAST('2000-1-1' AS DATE) ) <= COALESCE (:datefrom, now())
        AND COALESCE (pc.dateto, CAST('2200-12-31' AS DATE) ) >= COALESCE (:dateto, now())

Dao call :

@Transactional(readOnly = true)
public List<PriceListDto> ReportCatPriceList(Long idk, Date dateFrom, Date dateTo) {
    Query query = EM.createNativeQuery(queryReport, PersonProductsByDay.class)
        .setParameter("idCat", idk)
        .setParameter("datefrom", dateFrom, TemporalType.DATE)
        .setParameter("dateto", dateTo, TemporalType.DATE);

    return query.getResultList();
}

Answer 3

Using Hibernate specific Session API works as a workaround:

String sql = "INSERT INTO person (id, name) VALUES (:id, :name)";
Session session = em.unwrap(Session.class);
SQLQuery insert = session.createSQLQuery(sql);
sql.setInteger("id", 123);
sql.setString("name", null);
insert.executeUpdate();

I've also filed HHH-9165 to report this issue, if it is indeed a bug.

Answer 4

If you are willing to use the PreparedStatement class instead of Query:

if (entity.getHistory() == null)
    stmt.setNull(6, Types.VARCHAR);
else
    stmt.setString(6, entity.getHistory());

(It is possible that using ?::text in your query string would also work, but I've never done it that way myself.)

Answer 5

I had the same problem executing an UPDATE with Oracle Database. Sometimes a few fields that are updated are null and this issue occurs. Apparently JPA is casting my null value into bytea as already spoke in this topic.

I give up of using the Query object to update my table and used the EntityManager.merge(Entity) method.

I simply create the Entity object with all informations and when I execute the merge(Entity), the JPA executes a SELECT, compares the information already persisted on the Data Base with my Entity object and executes the UPDATE correctly. That is, JPA create a "field = NULL" sentence for the Entity variables that are null.

Answer 6

You can cast the parameter to a proper type in the query. I think this solution should work for other databases, too.

Before:

@Query("SELECT person FROM people person"
     + " WHERE (?1 IS NULL OR person.name = ?1)")
List<Person> getPeopleWithName(final String name);

After:

@Query("SELECT person FROM people person"
     + " WHERE (?1 IS NULL OR person.name = cast(?1 as string))")
List<Person> getPeopleWithName(final String name);

Also works for LIKE statements:

person.name LIKE concat('%', cast(?1 as string), '%')

and with numbers (here of type Double):

person.height >= cast(cast(?1 as string) as double)