Select table row using HQL with param

Question

I want to use this HQL query in order to select table row value:

String hql = "select e.token, e.name from Terminals e where e.token = ?";
Terminals terminal = entityManager
    .createQuery(hql, Terminals.class)
    .setParameter(0, terminalToken)
    .getSingleResult();

But I get this result:

java.lang.IllegalArgumentException: Cannot create TypedQuery for query with more than one return using requested result type [org.api.entity.Terminals]

What is the proper way to implement this?

score 2 · Answer 1 · answered Jul 22 '18 at 21:01

2

Your query return two Objects token and name and not a Terminals Object.

Instead you can use :

Object[] obj = entityManager
    .createQuery(hql)
    .setParameter(0, terminalToken)
    .getSingleResult();

if(obj != null){
    Terminals terminal = new Terminals((String) obj[0], (String) obj[1]);
}

Or you can create a constructor in Terminals class which hold two fields :

public Terminals(String token, String name){
   this.token = token;
   this.name = name;
}

then change your code to be :

String hql = "select new com.package.Terminals(e.token, e.name) from Terminals e where e.token = ?";
Terminals terminal = entityManager
    .createQuery(hql, Terminals.class)
    .setParameter(0, terminalToken)
    .getSingleResult();

answered Jul 22 '18 at 21:01

YCF_L

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By the way is there a better more simple way? – Peter Penzov Jul 22 '18 at 21:06
@PeterPenzov mmm I'm not sure, all I know is this two ways, unless you want to return the full Object you don't need all that just change your query to be `"select e from Terminals e where e.token = ?";` this will return the full Terminals Object – YCF_L Jul 22 '18 at 21:09
@PeterPenzov Just change your query to be `"select e from Terminals e where e.token = ?";` – YCF_L Jul 22 '18 at 21:11
I updated the code but the selected object values are null. Any idea why? – Peter Penzov Jul 22 '18 at 21:17
@PeterPenzov are you sure you have a value with the token you enter in your database? – YCF_L Jul 22 '18 at 21:30
Yes, anyway I will try to hard code the value just to test. – Peter Penzov Jul 22 '18 at 22:03

Aman · Answer 2 · 2018-07-22T21:13:20.530

IMO, you should not directly call createQuery to assign to a custom object. And there is a possiblity of returning a list.

Query query = entityManager.createQuery(hql).setParameter(0, "something");<br>
List<Object[]> terminals = query.getResultList();

and retrieve the objects with an index as the ff as an example:

        StudentDto dto = new StudentDto();
        for(Object[] a: std) {
            dto = new StudentDto();
            dto.setId((long) a[0]); //id
            dto.setName(a[1].toString()); //first name
            dto.setPassportNumber(a[2].toString()); //last name
        }

Select table row using HQL with param

2 Answers2