Sure, there may be a chicken and egg situation between Hibernate and JPA, but I'm trying to understand why this was specified the way it is, as I find this quite surprising.
2018-02-22 10:59 GMT+01:00 andrea boriero <and...@hibernate.org>: > Hi Lukas, > > I think it is based on JPA 2.1 spec, 4.4.4 Path Expressions , "Path > expression navigability is composed using “inner join” semantics." > > On 22 February 2018 at 08:09, Lukas Eder <lukas.e...@gmail.com> wrote: > >> Hello, >> >> Vlad Mihalcea  was so kind to point me to this mailing list with my >> question about implicit joins. The user guide  states that: >> >> "Implicit joins are always treated as inner joins." >> >> To me, this seems wrong, semantically, if implicit joins follow optional >> (nullable) foreign key relationships. Let's assume that customers have >> optional addresses. When we write >> >> SELECT c.firstName, c.lastName, c.address.city.country.code >> FROM customer c >> >> The resulting query will INNER JOIN the customer / address / city / >> country >> tables, filtering out customers with no address, or addresses with no >> cities, or cities with no countries (let's ignore the modelling aspect). >> In >> fact, I got a CROSS JOIN with join predicate in the WHERE clause, but that >> doesn't really change anything. Hence the SELECT clause applies a filter, >> which is rather surprising. To me, this seems simply wrong just like it >> would be wrong for Stream.map() to apply any filters. >> >> However, I'm sure there must have been good reasons to default to this >> behaviour, even in the presence of optional foreign keys. >> >> Does anyone know what those reasons are? >> Cheers, >> Lukas >> >> : https://twitter.com/vlad_mihalcea/status/965927462684196864 >> : http://docs.jboss.org/hibernate/orm/5.2/userguide/ >> html_single/Hibernate_User_Guide.html#hql-implicit-join >> _______________________________________________ >> hibernate-dev mailing list >> firstname.lastname@example.org >> https://lists.jboss.org/mailman/listinfo/hibernate-dev >> > > _______________________________________________ hibernate-dev mailing list email@example.com https://lists.jboss.org/mailman/listinfo/hibernate-dev