Not tested or compiled
object isLab extends MappedBoolean(this)
1.
def source: Box[Source] = if(isLab.is) lab.obj else scientist.obj
def source_=(s: Source) = s match {
case l: Lab => isLab(true); lab(l)
// same for scientist
}
2.
object source extends MappedLong {
def obj = if(isLab) Lab.find(is) else Scientist.find(is)
def obj_=(s: Source) = s match {
case _: Lab => set(s.id)
// same for scientist
}
The advantage of 1 is database FK constraints.
The advantage of 2 is fewer fields.
-------------------------------------
Mads Hartmann<mads...@gmail.com> wrote:
Thank you for taking your time to answer my question
I don't think I fully understand how to implement any of the suggested
solutions, if you have the time I would love a code example :)
Thanks a lot,
Mads Hartmann Jensen
On Feb 5, 7:34 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
> Basically, either use two protected LongMappedMappers and a public
> getter/setter that takes a boolean into account in both directions; or use a
> MappedLong, with
> def obj = whicheverLookUpTable.find(this.is)
> and
> override def set(s: Source) = s match ...
>
> Sorry for the brevity, if unclear please ask.
>
> -------------------------------------
>
> Mads Hartmann<mads...@gmail.com> wrote:
>
> Naftoli would you please re-post your solution :) I could really use
> the help
>
> On Feb 5, 6:56 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
>
>
>
>
>
> > Peek --www.getpeek.com
> > Please forward any bad messages to feedb...@getpeek.com
>
> > -------------------------------------
>
> > Ross Mellgren<dri...@gmail.com> wrote:
>
> > This is actually fairly common that messages Naftoli sends are empty, or
> > don't get threaded onto the original discussion, or formatting comes out
> > funny. Naftoli, what email client are you using?
>
> > -Ross
>
> > On Feb 5, 2010, at 1:49 AM, Mads Hartmann wrote:
>
> > > Hey Naftoli,
> > > I think something might have broken your first message, It's a blank
> > > message if you view it through the web-interface:
> > >http://groups.google.com/group/liftweb/browse_thread/thread/e2317e5db...
>
> > > If you have a solution I would love to hear it :)
>
> > > On Feb 5, 1:52 am, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
> > >> Does my approach not work?
>
> > >> -------------------------------------
>
> > >> Mads Hartmann<mads...@gmail.com> wrote:
>
> > >> Yeah that helped, my lab and scientist now looks like this:
>
> > >> /------------------------------- code
>
> > >> trait BaseSourceTrait[ T <:BaseSourceTrait[T] ] extends
> > >> LongKeyedMapper[T] {
>
> > >> self: T =>
>
> > >> override def primaryKeyField = id
> > >> object id extends MappedLongIndex(this)
>
> > >> object name extends MappedPoliteString(this, 256)
> > >> object sourceType extends MappedEnum(this,SourceTypes)
>
> > >> object SourceTypes extends Enumeration {
> > >> val Scientist = Value("Scientist")
> > >> val Lab = Value("Lab")
> > >> }
>
> > >> }
>
> > >> class Scientist extends BaseSourceTrait[Scientist] {
>
> > >> def getSingleton = Scientist
>
> > >> object birth extends MappedInt(this)
> > >> object death extends MappedInt(this)
> > >> object nationality extends MappedPoliteString(this, 128)
>
> > >> }
>
> > >> object Scientist extends Scientist with LongKeyedMetaMapper[Scientist]
> > >> {
> > >> override def dbTableName = "Source"
>
> > >> }
>
> > >> class Lab extends BaseSourceTrait[Lab] {
>
> > >> def getSingleton = Lab
>
> > >> object institution extends MappedLongForeignKey(this, Institution)
>
> > >> }
>
> > >> object Lab extends Lab with LongKeyedMetaMapper[Lab] {
> > >> override def dbTableName = "Source"
>
> > >> }
>
> > >> /------------------------------- code ends
>
> > >> My only problem now is that I can't figure out how to implement the
> > >> following:
>
> > >> A Discovery (a mapped class) needs to have a foreign key to the source
> > >> that made the discovery, this could be either a lab or a scientist, so
> > >> normally i would have a field with a reference to the super-class of
> > >> both Scientist and Lab - However, I don't have a super-class, I just
> > >> have a trait :)
>
> > >> I would like to be able to write something like this:
>
> > >> /------------------------------- code starts again
>
> > >> class Discovery extends LongKeyedMapper[Discovery] with IdPK {
>
> > >> def getSingleton = Discovery
>
> > >> // primatives
> > >> object description extends MappedDateTime(this)
> > >> object year extends MappedInt(this)
> > >> object reference extends MappedPoliteString(this, 128)
>
> > >> // relationships
> > >> object source extends MappedLongForeignKey(this,
> > >> BaseSourceTrait) //
> > >> <-- this is what i want.
>
> > >> }
>
> > >> object Discovery extends Discovery with LongKeyedMetaMapper[Discovery]
>
> > >> /------------------------------- code ends
>
> > >> As always I truely appreciate the help you guys are giving me :)
>
> > >> Thanks,
> > >> Mads Hartmann Jensen
>
> > >> On Feb 4, 9:56 pm, David Pollak <feeder.of.the.be...@gmail.com> wrote:
>
> > >>> Please take a look at the MegaProtoUser and MegaMetaProtoUser code for
> > >>> examples of how to create traits that can be mixed into classes.
>
> > >>> Does that help?
>
> > >>> On Thu, Feb 4, 2010 at 9:58 AM, Mads Hartmann Jensen
> > >>> <mads...@gmail.com>wrote:
>
> > >>>> hello Jeppe,
>
> > >>>> In my project I've got the following three models: A discovery, a
> > >>>> Scientist
> > >>>> and a lab. The Discovery has been invented by someone, this is either a
> > >>>> single scientist or sometimes a lab - This is easily done through
> > >>>> inheritance (would create a superclass named source) but I'm not sure
> > >>>> how to
> > >>>> do this so it maps nicely to the database.
>
> > >>>> Scientist and Lab only share one attribute so what I'm most interested
> > >>>> in
> > >>>> is to be able express that a Discovery has s source that can be either
> > >>>> a lab
> > >>>> or scientist :)
>
> > >>>> Hope this explains my problem more clearly, thanks for the help
>
> > >>>> Mads Hartmann
>
> > >>>> Sent from my iPhone
>
> > >>>> On 04/02/2010, at 18.17, Jeppe Nejsum Madsen <je...@ingolfs.dk> wrote:
>
> > >>>> Mads Hartmann <mads...@gmail.com> writes:
>
> > >>>>> Hello Everyone,
>
> > >>>>>> I'm currently trying to figure out how to map objects with
> > >>>>>> inheritance
> > >>>>>> using the Mapper framework. I've got a Lab and a Scientist who
> > >>>>>> inherit
> > >>>>>> from Source.
>
> > >>>>>> As I understand there's no direct way to do inheritance using the
> > >>>>>> Mapper framework so I'm trying to figure out how to implement 'Single
> > >>>>>> Table Inheritance'.
>
> > >>>>>> Right now I'm trying to create a single trait (Source) for the values
> > >>>>>> that they share called BaseSource and my idea is to mix it in both
> > >>>>>> Lab
> > >>>>>> and Scientist. I would then define the table name of both scientist
> > >>>>>> and lab to be the same - I think this would work but what I'm not
> > >>>>>> sure
> > >>>>>> of is the following:
>
> > >>>>>> - If both Scientist and Lab mixes in the IdPK trait and use the same
> > >>>>>> table, will the id still be unique?
> > >>>>>> - A Discovery has a source, how do i create MappedLongForeignKey to
> > >>>>>> the table they share (lab, scientist)?
>
> > >>>>>> I hope you'll be able to help me out :)
>
> > >>>>> I can't say I follow the above :-) Do you want to share tables, code
> > >>>>> or
> > >>>>> both? Maybe list the table structure and explain how you would like to
> > >>>>> map it....
>
> > >>>>> /Jeppe
>
> > >>>>> --
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