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

[Lerner, Dave]

Hi Alex,

> 
> 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 query in question is not required any longer after Belen's answer. I didn't know multiple images  per build-id were possible.

However, to get a list of a package's dependent packages' names, across a many-to-many relation, in package.html, given a package id, you use two queries to print dependent package names in the template, due to the many-to-many relation...
the reverse lookup :
	{% for d in package.package_dependencies_source.all %}

and then the implicit query from package dependency back to package
           <a href="#{{d.name}}">{{d.depends_on.name}}</a><br/>

The standard sql-92 query syntax below will construct a list of package names of dependent packages in a single query rather than the iteration technique above in the package.html template.  

		
		 'SELECT 
			orm_package_dependency.id, 
            	orm_package.name name, 
			orm_package.version version, 
			orm_package.size size 
            FROM 
			orm_package, 
			orm_package_dependency 
            WHERE 
			 orm_package_dependency.package_id = %s 
            AND  orm_package_dependency.dep_type == 0 
            AND  orm_package.id = orm_package_dependency.depends_on_id
		 ', [package_id])

I want to use django model query apis because, as you mention, we can't easily validate whether a query is sql-92 and portable.  

I got as far as getting the set of package_dependencies for RDEPENDS packages on somePackageKey
    package = Package.get(id=somePackageKey)
    package_dependencies = package.package_dependencies_source(dep_type_exact=0)
but couldn't work out syntax to get from this Package_Dependency set to the Package set without iteration in either the client or server.  Do you have a trick other than iterating through this list (in either the server or ugh-client?)

-Dave

> 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