[hibernate-dev] boolean type support

[Vlad Mihalcea]

If you think we can handle this better using Attributes, then we can give
it a try.

Nevertheless, the current implementation is nice as well. We have a single
Java descriptor and multiple Sql descriptors to cover various DB column
types or column values.

Vlad

On Fri, Jan 27, 2017 at 8:28 PM, Steve Ebersole <steve at hibernate.org> wrote:

> Correction : If they have not done that either, we'd simply *ask* the
> Dialect.
>
> On Fri, Jan 27, 2017 at 12:24 PM Steve Ebersole <steve at hibernate.org>
> wrote:
>
> > On Fri, Jan 27, 2017 at 10:46 AM Christian Beikov <
> > christian.beikov at gmail.com> wrote:
> >
> > Am 27.01.2017 um 17:31 schrieb Steve Ebersole:
> > > Obviously that only works if there is not already an AttributeConverter
> > > applied to to the attribute.  I cannot imagine that ever happens in a
> > > supported way, or a way that we want to support.  Essentially that
> would
> > > mean a condition where we convert the value twice in each direction.
> But
> > > in case we miss some ase, I wanted to ask the list.
> > So if a user defines a converter for Boolean=>Enum for example, that
> > would not work on e.g. Oracle since on such a DB the column type is
> > integer?
> >
> >
> > I am not following what you mean.  Why would an enum be a boolean?  You
> > mean something like:
> >
> > enum Sex { MALE, FEMALE )
> >
> > and then storing into the DB as `IS_MALE`?
> >
> > I mean I guess someone *could* write an app that way.  I'd laugh at them,
> > but I guess they could ;)
> >
> > Anyway, they can already do that... it called an AttributeConverter :P
> >
> > More I am asking about the legacy BooleanType, YesNoType and
> > TrueFalseType.  These each used different JavaTypeDescriptor instances
> > encoding the specific true/false DB ('Y'/'N', 'T'/'F', 1/0, ..)
> > representations.
> >
> > So in stepping back and thinking about how this "should" be designed, I
> am
> > thinking that the most logical design is to have just a single
> > JavaTypeDesriptor for boolean and to somehow keep the specific DB storage
> > representations as part of the attribute[1].
> >
> > But then we start thinking how that should affect the wrap/unwrap
> > process.  Well, we already have a way for attribute-level "config" to
> alter
> > the wrap/unwrap process - again, AttributeConverter.  So at the minimum
> we
> > will handle this in the same manner as we hande AttributeConverter.  But
> > then we asked whether we might just *use* AttributeConverter for this;
> this
> > design works well, so long as these attributes do not also have an
> > AttributeConverter associated with them.
> >
> > I think I'd propose this...
> >
> > We'd essentially say that we do not natively understand how to store
> > booleans (just bear with me...).  Specifically how to convert them into a
> > DB storable format.  Which means we'd need something to help us perform
> > that conversion.  If the user has attached an AttributeConverter to the
> > attribute we'd simply use that.  If they have not, then we'd look to this
> > config option to see if they have specified how to do that globally.  If
> > they have not done that either, we'd simply as the Dialect.
> >
> >
> > [1] I'd never do this, but it is entirely possible that a user would want
> > a boolean value from one attribute stored in the DB as 0/1 and another
> > attribute store as Y/N.  So attribute is the highest granularity we need
> to
> > resolve this at.  But they might instead very well want to store all
> > boolean values in their app to the DB as a single representation - we'd
> > support that via config, as well as fallback to Dialect
> >
> >
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