Re: [hibernate-dev] 5.0 defaults
I mentioned my concerns about hibernate.implicit_naming_strategy and
auto-quoting keywords when I was getting the standalone TCK working with
master.
Here are my thoughts...
On 08/03/2015 02:17 PM, Steve Ebersole wrote:
1) hibernate.implicit_naming_strategy - by default Hibernate uses
its
legacy implicit naming strategy which predates the clarifications made in
JPA 2.0 by many years. The question here is whether we want to change
this
(now/ever) to use the JPA (2.0) compliant one?
IMO, the JPA annnotations should generate tables/columns/etc that are
JPA-compliant by default. If a developer is adding JPA annotations, I think
there is a pretty good likelihood they will be referring to Javadoc or
looking at the annnotations interface itself in an IDE. I think there would
be an expectation that the generated names due to the JPA annotations would
be consistent with what is documented. I think there is also an expectation
that the generated names would be portable.
Here are some examples of bugs I fixed in 4.2/4.3 where generated names
were not consistent with JPA2:
- HHH-9387 (generated table name for @ElementCollection uses entity class
name; should use entity name);
- HHH-9389 (generated join column for @ElementCollection uses entity class
name; should use entity name);
- HHH-9390 (generated foreign key column name for unidirectional
@ManyToMany uses owning entity primary table name; should use owning entity
name.
I agree that 4.2/4.3 was not the proper time to make those changes the
default because it would be a breaking fix that would affect existing
applications.
IMO, 5 is a good place to make JPA-compliant naming the default. It would
still be a breaking change. Existing applications would need to make
necessary changes to either the JPA annotations or to the database objects
themselves to become JPA-compliant (and portable).
2) hibernate.auto_quote_keyword - by default we decided to have Hibernate
automatically quote identifiers it thinks are key/reserved words in the
underlying database. We know at the moment this is a bit too aggressive
as
it pulls in all of SQL:2003 defined keywords. The question is
whether we
disable this by default?
I think it will take some time to get the keyword list right for each
dialect. I wouldn't be surprised if different versions of a DBMS would have
different keywords. This could complicate things as most dialects are used
for multiple versions of a DBMS.
If 5.0.0 is released with auto-quoting as a default, and a later 5.0.x
version excludes keywords, it will be a breaking change for applications
that were developed or migrated to an earlier 5.0 version.
Also, auto-quoting keywords (only) is not JPA-compliant.
I would be more comfortable if auto-quoting keywords is considered
experimental, and not the default behavior.
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