Question

I am currently working on a project to transfer some legacy jdbc select statements over to using Hibernate and it’s criteria api.

The two relevant table columns and the SQL query looks like:

-QUERIES-
primaryId

-QUERYDETAILS-
primaryId
linkedQueryId -> Foreign key references queries.primaryId
value1
value2

select * 
from queries q 
where q.primaryId not in (SELECT qd.linkedQueryId 
                          FROM querydetails qd 
                          WHERE (qd.value1 LIKE 'PROMPT%' 
                                 OR qd.value2 LIKE 'PROMPT%'));

My entity relationships look like:

@Table("queries")
public class QueryEntity{

    @Id
    @Column
    private Long primaryId;
    @OneToMany(targetEntity = QueryDetailEntity.class, mappedBy = "query", fetch = FetchType.EAGER)
    private Set<QueryDetailEntities> queryDetails;

    //..getters/setters..

}

@Entity
@Table(name = "queryDetails")
public class QueryDetailEntity {
    @Id
    @Column
    private Long primaryId;

    @ManyToOne(targetEntity = QueryEntity.class)
    private QueryEntity query;

@Column(name="value1")
private String value1;

@Column(name="value2")
private String value2;

    //..getters/setters..

}

I am attempting to utilize the criteria api in this way:

Criteria crit = sessionFactory.getCurrentSession().createCriteria(QueryEntity.class);

DetachedCriteria subQuery = DetachedCriteria.forClass(QueryDetailEntity.class);
LogicalExpression hasPrompt = Restrictions.or(Restrictions.ilike("value1", "PROMPT%"),
        Restrictions.ilike("value2", "PROMPT%"));
subQuery.add(hasPrompt);
Criterion subQueryCrit = Subqueries.notIn("queryDetails", subQuery);
crit.add(subQueryCrit);

List<QueryMainEntity> entities = (List<QueryMainEntity>) crit.list();
System.out.println("# of results = " + entities.size());

I am getting a NullPointerException on the crit.list() line that looks like

Exception in thread "main" java.lang.NullPointerException
    at org.hibernate.loader.criteria.CriteriaQueryTranslator.getProjectedTypes(CriteriaQueryTranslator.java:362)
    at org.hibernate.criterion.SubqueryExpression.createAndSetInnerQuery(SubqueryExpression.java:153)
    at org.hibernate.criterion.SubqueryExpression.toSqlString(SubqueryExpression.java:69)
    at org.hibernate.loader.criteria.CriteriaQueryTranslator.getWhereCondition(CriteriaQueryTranslator.java:380)
    at org.hibernate.loader.criteria.CriteriaJoinWalker.<init>(CriteriaJoinWalker.java:114)
    at org.hibernate.loader.criteria.CriteriaJoinWalker.<init>(CriteriaJoinWalker.java:83)
    at org.hibernate.loader.criteria.CriteriaLoader.<init>(CriteriaLoader.java:92)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1687)
    at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:347)

Now, I think its pretty safe to say I’m using the Criteria Api/Detached Query Api incorrectly, but I’m not sure what the ‘correct’ way to do it is since the Hibernate Docs only briefly cover criteria api subqueries.

I realize this is a pretty long question, but I figure its appear to put it all the relevant aspects of the question (query I’m attempting to represent via Criteria API, tables, entities).

Answer 1

Give this a shot:

DetachedCriteria d = DetachedCriteria.forClass(QueryDetailEntity.class, "qd");
d.setProjection(Projections.projectionList().add(Projections.property("qd.query")));
d.add(Restrictions.or(Restrictions.like("qd.value1", "PROMPT%"), Restrictions.like("qd.value2", "PROMPT%")));

criteria = session.createCriteria(QueryEntity.class, "q");
criteria.add(Subqueries.propertyNotIn("q.primaryId", d));
criteria.list();

The use of the following are property names, not column names:

qd.query
qd.value1
qd.value2
q.primaryId

As a side note, if this is not a dynamically generated query, have you given thought to using HQL instead?