[Opensource] multi-valued fields towards multipleselectboxes

[Lirian Ostrovica]

Hi Larry,

This question is not simply my personal concern, as I can fix it in a customized (my own) way.
The point is that I think that this deserves to be an Expresso issue, which means that we ought to find an optimal and reusable solution.

Again, in practical terms, an example of when the problem rises is:

If users have to have some registration information that is expressed through a multiple choice box, we CAN NOT use an Epresso RegistrationDBObject to save this user registration information in the database.
As consequence the whole Expresso's user administration support becomes obsolete.

As I explained previously, going deeper, I do not see this as an RegistrationDBObject issue, but I see it as a DBObject issue, because the there can be other cases in which one would like to automatically
map an HTML FORM to the database and vice versa.

As I said before the automatic mapping HTML FORM - DBObject already exists in Expresso and it is nicely used in the case of RegistrationDBObjects, but it falls short if the Html Form contains one ore more
multiple choice boxes.

Thank you

Lirian



larry hamel wrote:

> perhaps I don't understand the question, but consider an association table
>
> definition_table  # this defines the pull down list
>         poss_values
>
> association_table
>         user_id
>         chosen_value # foreign key on poss_values
>
> so long as there is no unique key which includes both these fields in in association table, multiple rows can be written for the same user_id (it can be other than user_id--whatever association you need)
>
> you mentioned "multi-valued" dbobjects, but have you seen MultiDBObject.java?  it may apply here.
>
> larry
>
> At 06:27 AM 3/21/2003, you wrote:
> >Hi Dave and Mike,
> >Thanks for the quick answers.
> >Back to the same issue, my concern is in fact on the persistence layer (I have
> >already resolved on my own way the presentation and the form data collection,
> >much like you guys did)
> >
> >My question is :
> >How do I store  into database the field values  coming from a multiple select
> >MenuBox.
> >What kind of DBObject field would be able to do that ?
> >
> >In other words :
> >A DBObject record (or instance) can be presented in a HTML FORM, but the way
> >around is not always possible.
> >If the html form contains a multiple select box or a group of checkboxes, I can
> >not represent it as a DBObject field.
> >
> >In my practical case, I have some Registration Info for my users that consist of
> >multiple selection, and I can not use the
> >Expresso Registration Object for them.
> >
> >My first thoughts have been about either playing with a regular DBObject field,
> >whose value will be a delimiter separated string of the selected values, or
> >playing with the multi-valued DBObject fields.
> >
> >looking forward to any idea or opinion
> >
> >Lirian
> >
> >
> >
> >Michael Rimov wrote:
> >
> >> At 10:52 AM 3/20/2003 -0500, you wrote:
> >> >Expreso provides for automatically generating a HTML FORM FIELD, that would
> >> >correspond to a DBObject FIELD, and be used to update the field value.
> >> >A typical example is the generation of HTML forms for Registration Objects.
> >> >
> >> >I need that one field of my registration information be a multiple choice
> >> >MenuBox.
> >> >In DBObject terms this would mean that I need a multi-valued field, whose
> >> >value
> >> >be A SET of some of those valid values.
> >> >DBObject multi-valued fields go fine with html MenuBoxes that allow only a
> >> >single choice (multiple=false), but how about the multiple choices ?
> >> >So my question is :
> >> >1 - Does Expresso have any support for this kind of field. (I looked a bit
> >> >through the source code and could not find any clue).
> >> >2 - If not, has anyone used any work around to this.
> >>
> >> Lirian,
> >>
> >> Multiple selects in menu boxes are, indeed, not directly
> >> supported.  Multiple checkboxes can be supported by giving each checkbox a
> >> unique ID number... I've done it that way in a couple of projects, and
> >> although the jsp is a little weird it makes the code on the expresso side
> >> much easier.
> >>
> >> To deal with multiple selections of the same name, you'll need to downcast
> >> ControllerRequest to ServletControllerRequest so you can get a List of all
> >> parameters, not just a Map of them.
> >>
> >> HTH!
> >>                                                  -Mike
> >>
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