Thanks for the response. I believe I understand your suggestion. DBs are not
one of my areas of strength, and so I'm struggling with issues that may be
simple. So, I have a few follow up questions:
Question 1
In:
db.define_table('application',
Field('name'),
Field('version'),
format='%(name)s %(version)s')
What is the purpose of the 'format' argument? Does it some how control how a
pull down menu is formated? or how each row is printed in a report? or is it
some proper DB thing?
Question 2
How should I understand the statement:
db.application.version.
>
> requires=IS_NOT_IN_DB(db
> (db.application.name==request.vars.name),db.application.version)
First, what is it suppose to mean? Something like "allow the update if and
only if rows who's name matches the request's name do not already have the
given version"?
Second, I can't make sense of the second argument. Doesn't it just evaluate
to a boolean, and get passed into IS_NOT_IN_DB()? Does the code get reparsed
for every form and row? How does it work? I assume the intent is that the
second argument is some sort of function that get evaluated against each
row.
Question 3
Somehow I've assumed that when I'm defining a table that it's all DB
specific, but it seems that I'm also specifiying the GUI presentation --
pull down menus and so on. Is this correct and intentional?
Thank you,
C. Helck
On Sun, Dec 27, 2009 at 11:55 PM, mdipierro <[email protected]> wrote:
> First of all let me congratulate for the clear format of your
> question.
> This line:
>
> db.report.from_id.requires = IS_IN_DB(db, db.version.id, '%(name)s
> %(version)s') # Again, I want a set, not a list.
>
> does not display the cartesian product of name and version but only a
> list of name, version for every record in db.version. Some entries are
> repeated because name+version is not a unique key of db.version.
>
> As I see it this is a logical problem.
>
> The table version contains a link between an application version and a
> component version. It basically implements a many-2-many relation but
> without a source table. The missing source table is the one you want
> to reference in from_id. The source table is a table that contains
> lists of application name,version and all entries are unique.
>
> My suggestion is change the model:
>
> db.define_table('application',
> Field('name'),
> Field('version'),
> format='%(name)s %(version)s')
> #make sure name+version is unique for applications
> db.application.version.requires=IS_NOT_IN_DB(db
> (db.application.name==request.vars.name),db.application.version)
>
> db.define_table('component',
> Field('name'),
> Field('version'(,
> Field('label'),
> format='%(name)s %(version)s')
> )
> #make sure name+version is unique + components
> db.component.version.requires=IS_NOT_IN_DB(db
> (db.component.name==request.vars.name),db.component.version)
>
> db.define_table('usage',
> Field('application_id', db.application),
> Field('component_id', db.component))
>
> db.define_table('report',
> Field('from_id', db.application),
> Field('to_id', db.application))
>
> If you use 1.74.4 and the format attribute you do not need to set any
> of the IS_IN_DB validators. I think this will be what you want. The
> tables "applicaiton" and "usage" replace your table "version".
>
> On Dec 27, 9:18 pm, Christopher Helck <[email protected]>
> wrote:
> > I apologize if this is more of a DB question than a web2py question, but
> I'm
> > having trouble with populating a drop down menu in the admin interface. I
> > have a table (called 'version') with two keys ('name' and 'version')
> and a
> > third column 'component_id'. This table records which versions of an
> > application use which software component: Example data:
> >
> > Name, Version, Component
> > credit, 1.0.0 commons_all_1.2
> > credit, 1.0.1, commons_all_1.3
> > credit, 1.0.0 commons_pools_6.3
> > credit, 1.0.1, commons_pools_6.5
> >
> > Interpretaion: The credit application 1.0.0 uses commons_all_1.2 and
> > commons_pools_6.3
> > The credit application 1.0.1 uses commons_all_1.3 and
> > commons_pools_6.5
> >
> > The problem occurs when I reference the version table from another table.
> > The drop down list contains:
> > credit 1.0.0
> > credit 1.0.0
> > credit 1.0.1
> > credit 1.0.1
> >
> > I want the drop down menu to display the set {name, version}, instead of
> the
> > cartisian product of the two keys. Here's my db.py:
> >
> > db.define_table('component',
> > Field('component_name'),
> > Field('component_version'),
> > Field('label'))
> >
> > db.define_table('version',
> > Field('name'),
> > Field('version'),
> > Field('component_id', db.component))
> >
> > db.define_table('report',
> > Field('from_id', db.version), # Drop down menu has
> cartisian
> > product of version.name X version.version
> > Field('to_id', db.version))
> >
> > db.version.component_id.requires = IS_IN_DB(db, db.component.id,
> > '%(component_name)s %(component_version)s')
> > db.report.from_id.requires = IS_IN_DB(db, db.version.id, '%(name)s
> > %(version)s') # Again, I want a set, not a list.
> > db.report.to_id.requires = IS_IN_DB(db, db.version.id, '%(name)s
> > %(version)s')
> >
> > Thanks,
> > C. helck
>
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