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From Michael Gentry <blackn...@gmail.com>
Subject Re: Lazy Attributes
Date Fri, 29 Nov 2019 16:02:10 GMT
Well, update the JIRA I just created!  :-)

https://issues.apache.org/jira/browse/CAY-2641


On Fri, Nov 29, 2019 at 10:57 AM Hugi Thordarson <hugi@karlmenn.is> wrote:

> This sounds very nice…
>
> To do a little dreaming, it would be even more awesome if property
> lazyness was controllable on a per-query basis, usage requirements tend to
> be quite dependent on context.
>
> A bit like a ColumnSelect that still allows you to keep all your fancy
> DataObject business logic intact :).
>
> ObjectSelect
>         .query( BigEntity.class )
>         .lazyProperties( BigEntity.HUGE_IMAGE, BigEntity.MASSIVE_STRING )
>
> - hugi
>
>
>
> > On 29 Nov 2019, at 15:25, Michael Gentry <blacknext@gmail.com> wrote:
> >
> > Well, we can't always control the DB schema we have to interface with...
> >
> >
> > On Fri, Nov 29, 2019 at 5:30 AM Maik Musall <maik@selbstdenker.ag>
> wrote:
> >
> >> I’ll add a little caveat though. If a query hits lots of rows and thus
> the
> >> optimizer decides to do a full table scan (or a partition scan), the
> >> database could still end up having to read the blobs from disk, only
> >> omitting them in the returned results. So there may still be
> >> performance-related reasons to keep such blobs in separate entities (or
> >> elsewhere), depending on the specific RDBMS and it’s configuration.
> >>
> >>> Am 29.11.2019 um 07:07 schrieb Lon Varscsak <lon.varscsak@gmail.com>:
> >>>
> >>> Yeah, it's a great idea.
> >>>
> >>> On Thu, Nov 28, 2019 at 6:06 AM Maik Musall <maik@selbstdenker.ag>
> >> wrote:
> >>>
> >>>> +1 sounds very useful to simplify the data model here and there
> >>>>
> >>>>> Am 27.11.2019 um 13:06 schrieb Michael Gentry <blacknext@gmail.com>:
> >>>>>
> >>>>> I just happened across an article on Hibernate which talks about
lazy
> >>>>> attributes.  (A recent addition, I think.)  This essentially allows
> you
> >>>> to
> >>>>> flag an attribute/column as lazy and it'll be excluded from the
> >> original
> >>>>> SELECT query, but if you call the getter it will then fetch it in.
> >> This
> >>>> is
> >>>>> convenient for BLOB-type data that might happen to be in a main
table
> >>>> with
> >>>>> other attributes (such as MIME types, file sizes, file names, etc).
> >>>>>
> >>>>> Thoughts on maybe adding this feature to Cayenne?  I can imagine
> >> there'd
> >>>> be
> >>>>> a "Lazy" column in Cayenne Modeler for the attributes to
> >> control/identify
> >>>>> them.
> >>>>>
> >>>>> Thanks,
> >>>>>
> >>>>> mrg
> >>>>
> >>>>
> >>
> >>
>
>

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