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Re: [eclipselink-users] Conditional LEFT JOIN in JPQL

Hi Vidas,

  You may want to look at our Dynamic JPA feature.  Here's a link to an example:

The feature is quite new and evolving quickly, so please post any issues you have to this forum.


Vidas Timukas wrote:
Hi, Frank,

Thanks for advice, but:

2010/5/7 Frank Schwarz <fs5@xxxxxxx <mailto:fs5@xxxxxxx>>

    The additional fields can also be mapped by a
    java.util.Map-structure, i.e.

    public class Country {
     private Map<String, String> extChatFields;

Yep, that's true, and my first version was in this direction, but, in my real application:

1) Tables extCharFields, extIntFields, extDateFields... can hold additional data also from other tables.

2) There is a big performance issue, because with collections, additional records are retrieved in separate calls to DB per every parent row, and in my solution I can get all required data with single SQL.
     With this mapping, you would even have transparent "write access" to

I also did this in my component :-)



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