HSQLDB with Hibernate: addScalar

  2013-09-18


{% include JB/setup %}

To continue this series, I just have another little cautionary bit of advice regarding using addScalar with your createSQLQuery(...) operations. In MySQL, a query like this:

SELECT obj.name, other.name, third.name FROM obj, other, third

Will give the full name of those columns in the “result set metadata” that Hibernate accesses. So when you use addScalar, you can just say:

.addScalar("obj.name") .addScalar("other.name") .addScalar("third.name")

However, in other database engines the columns might come back in the metadata as [ name, name, name ]; when you try to use addScalar with the full path, you will get an error. (I don’t believe that just calling addScalar once with “name” will apply to each of the three occurrences either, but I haven’t checked).

The way I solved it for HSQLDB isn’t rocket science:

SELECT obj.name objName, other.name otherName, third.name thirdName FROM obj, other, third