Hibernate + Derby: Comparisons between 'BOOLEAN' and 'INTEGER' are not supported

Question

I have a problem with querying Derby database. I am using Hibernate with JPA. Problem is related (probably) to boolean columns. Each query ends with error:

org.h

Answer 1

Used Rafal's approach but also have to add

@Override
public String toBooleanValueString(boolean bool) {
    return bool ? "1" : "0";
}

in my Dialect. Otherwise it doesn't work under Hibernate 4.2.8.

Also I wasn't be able to specify my dialect explicitly in persistence.xml as my app runs against Oracle and Derby. So I've added a dialect resolver for my dialect:

Resolver itself:

public class DerbyBoolAsIntDialectResolver extends AbstractDialectResolver {
    @Override
    protected Dialect resolveDialectInternal(DatabaseMetaData metaData) throws SQLException {
        String databaseName = metaData.getDatabaseProductName();
        int databaseMajorVersion = metaData.getDatabaseMajorVersion();

        if ( "Apache Derby".equals( databaseName ) ) {
            final int databaseMinorVersion = metaData.getDatabaseMinorVersion();
            if ( databaseMajorVersion > 10 || ( databaseMajorVersion == 10 && databaseMinorVersion >= 7 ) ) {
                return new DerbyBoolAsIntDialect();
            }
        }
        return null;
    }
}