Can I use hibernate query language for entities not mapped to a table?

Question

Following is the mySQL query that I am using to retrieve HolidayPackages for a given Hotel:

SELECT pkg.idHolidayPackage, pkg.name FROM holidaypackage pkg INNER JOIN holidaypackagehotel hph ON pkg.idHolidayPackage = hph.idHolidayPackage INNER JOIN hotelroom hr ON hr.idHotelRoom = hph.idHotelRoom WHERE hr.idHotel = 1;

I have POJOs with mapping for:

HolidayPackage
Hotel
HotelRoom

I don't have a POJO for HolidayPackageHotel.

Is there any way to use Criteria API or HQL to execute the sql query without creating a POJO for HolidayPackageHotel?

For the curios, DB relations:

Community · Accepted Answer · 2017-05-23 12:34:20Z

3

No. You can not use the un-mapped entities inside the HQL.

If you want to generate the List of beans from the query you can use the ResultSet transformers, which can convert the query results(object arrays) to beans. By doing this you will save the overhead of creating and filling the POJO beans.

Read here for an example.

edited May 23, 2017 at 12:34

CommunityBot

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answered Mar 20, 2012 at 9:02

ManuPK

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4 Comments

brainydexter Over a year ago

I used the following NamedNativeQuery: @NamedNativeQuery( name = "getHolidayPackageForHotel", query = "SELECT * FROM wah_schema.holidaypackage pkg INNER JOIN wah_schema.holidaypackagehotel hph ON pkg.idHolidayPackage = hph.idHolidayPackage INNER JOIN wah_schema.hotelroom hr ON hr.idHotelRoom = hph.idHotelRoom WHERE hr.idHotel = :idHotel", resultClass= HolidayPackage.class) This seemed to work for me, since the return type: HolidayPackage.class is a POJO entity I have defined. Do you think this approach has any drawbacks ?

ManuPK Over a year ago

In any query, SELECT * from is not a preferred approach. Add the column names in the select clause if possible. the rest is fine.

brainydexter Over a year ago

I get a Column 'IDHOTELROOM' not found if I use this: SELECT DISTINCT pkg.idHolidayPackage, pkg.name, pkg.itineraryHeader FROM wah_schema.holidaypackage pkg INNER JOIN wah_schema.holidaypackagehotel hph ON pkg.idHolidayPackage = hph.idHolidayPackage INNER JOIN wah_schema.hotelroom hr ON hr.idHotelRoom = hph.idHotelRoom WHERE hr.idHotel = ?

ManuPK Over a year ago

If you are running in to problems with NamedNativeQuery You can try the example given here.

Radim Köhler · Accepted Answer · 2013-05-29 07:27:53Z

yes, You can use the un-mapped entities inside the HQL.Below is the example what i did in one of my project.

List list = session.createQuery("select p, a from UserAccount p, Channels a " + "where p.uid = a.uid").list(); Iterator iter = list.iterator(); while (iter.hasNext()) { Object[] objArray = (Object[]) iter.next(); UserAccount p = (UserAccount) objArray[0]; Channels a = (Channels) objArray[1]; System.out.println(p.getUsername()); System.out.println(a.getTitle()); }

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