[Toaster] question on spec for "Package included in ..."

[Damian, Alexandru]

Hi Dave,

You should try not to think in terms of SQL queries, but instead in terms
of Django QuerySet queries.

The reason for this is that the SQL is often not portable across different
database backends, which is a requirement for Toaster because we want to
give infrastructure maintainers freedom on how they install Toaster and
which db backends they use.

The Django QuerySet to get the list of targets for a package can be derived
by following the relationship across models; i.e you get the build for the
specific package, and then you get the targets that are images for that
build; i.e.

> package = Package.objects.filter(pk = id)
> targets  = package.build.target_set.filter(is_image=True)

What happens here ?
  For the package model, build is a foreign key to the Build table, so
Django will populate the instance field with the correct object for Build
loaded from the database.
  The reverse dependency through a ForeignKey (i.e. many-to-one
relationship) is to be followed by convention: convert the desired object
set model name to lower case, and add "_set" to the name. This will create
a RelatedManager which is basically a QuerySet that can be filtered at will.
  The reverse dependency naming convention can be overridden by specifying
a "related_name" kwarg in the field model definition; this is needed when
you have two many-to-one relationships with the same object type, i.e. when
you map a many-to-many relationship, e.g. dependency tables.

Cheers,
Alex





On Mon, Jan 13, 2014 at 10:50 AM, Barros Pena, Belen <
belen.barros.pena at intel.com> wrote:

>
>
> On 12/01/2014 20:45, "Lerner, Dave" <dave.lerner at windriver.com> wrote:
>
> >Hi Belen, Alex
> >
> >I have a question about the intent of the specification on page 5 of 10
> >of spec design-1.5.1-package-details.pdf listing the images
> > that a package is included in.
> >
> >Packages included in target image
> >If
> > the package is installed in a build target image, the '1.5.1
> >Package
> > details' left content column shows only a list of
> >the
> > target images that include the package.
> >Each
> > target image is a link to the corresponding '1.1.1
> >Included
> > package details' page.
> >If
> > there is more than one target image in the build, they
> >are
> > separated by commas, and listed in ascending
> >alphabetical
> > order.
> >
> >
> >
> >
> >The list that should appear is clearly for the package
> >name-version-revision, but should it be a list restricted (as implied by
> > the breadcrumbs) to a single machine/bsp, for example atom-pc vs
> >qemuarm?
>
> The list includes only the targets of the selected build. Since there is a
> one to one relationship between builds and machines (you can only build
> for one machine at a time), the answer is yes, the targets listed will
> only apply to one machine. I'll try to explain a bit better: in the
> example shown in the spec (the one you have attached in your e-mail) you
> have selected, from your list of builds, a build for atom-pc that
> completed on 11th Jun 2013 at 15:22. That build built 3 targets:
> core-image-sato, core-image-sato-sdk and core-image-x11, all of them for a
> single machine (atom-pc). The package you have selected (base_files) was
> installed in all 3 targets, and so the 3 of them are listed at the top of
> the page.
>
> I hope this makes sense. If you have any questions, let me know. I'll let
> Alex answer the implementation part.
>
> Cheers
>
> Belén
>
> >Do I understand the view spec correctly?
> >
> >For that case, the current form of the database requires a complicated
> >query. I think the logic would have to be (for a passed in
> > build-id-arg, package-id-arg)
> >·
> >Get the machine,
> >buildMachine, for this build-id-arg
> >·
> >Get a list of package.id¹s for this list of
> >build.id¹s with this buildMachine
> >·
> >Get a list of target-installed-package.target_ids¹s that are in the
> >include the
> >package.id¹s above
> >·
> >Return a list of distinct
> >target.target using the target-insalled-package.target_ids list above and
> >also have
> >target.is_image true (1)
> >
> >or using $var embedded
> >sql syntax (for C), after buildMachine,
> >packageName, packageVersion,
> >packageRevision are retrieved...
> >
> >select distinct(orm_target.target) from
> >orm_target, orm_target_installed_package
> >where
> >
> >orm_target.is_image = 1
> >and orm_target.id =
> >orm_target_installed_package.target_id
> >and
> >orm_target_installed_package.package_id in
> >(select orm_package.id from
> >orm_build, orm_package
> >where
> >
> >orm_build.machine = $buildMachine
> >and orm_package.name = $packageName
> >and
> >orm_package.version = $packageVersion
> >and
> >orm_package.revision = $packageRevision
> >and orm_build.id =
> >orm_package.build_id);
> >
> >Thanks,
> >Dave Lerner
> >
> >
>
>


-- 
Alex Damian
Yocto Project
SSG / OTC
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