The default widget for a field with an IS_NOT_IN_DB requires is a text box. Your interpretation of how it should work is just one of possibly many. Think of it this way, the values in the db are a definite set, so you can create a list to choose one or many among them; the values that are not part of the db yet may not defined and can possibly be infinite e.g. books, stars, etc., so you can not list them.
In your case the db has all possible values but web2py does not know this. The solution is to use the complement of the set, all_booths minus leased_booths = free_booths, which is what you did. On Feb 4, 2:19 pm, SethKinast <[email protected]> wrote: > Hi, > > First off, I've already fixed my problem by coding it differently. > However, I was curious as to the proper way to set up this validator > so it shows a dropdown. > > I have two models, which can be simplified to: > > db.define_table('booth', > > Field('name','string',length=10,required=True,notnull=True,unique=True)) > db.define_table('lease', > Field('booth',db.booth), > Field('end_date','date')) > > When creating a new "lease", the SQLFORM field to pick a "booth" to > attach should only show booths which have no lease. So I added this in > the controller: > > def new(): > db.lease.booth.requires = IS_NOT_IN_DB(db(db.lease.end_date == > None)),'lease.booth') > > This promptly transformed the booth dropdown into a text box. It > worked fine if, when testing, I used IS_IN_DB instead (showing only > booths with current leases, which is of course backwards, but it > showed them as a dropdown). I know that if you put the validators in a > list they will not create dropdowns, and I made sure that my validator > was not in a list. > > So instead I switched to this: > > def new(): > leased_booths = db(db.lease.end_date == > None)._select(db.lease.booth) > db.lease.booth.requires = > IS_IN_DB(db(~(db.booth.id.belongs(leased_booths))),'booth.id','% > (name)s') > > which is a bit less efficient but displays the desired behavior. Is > there a more "web2py"-ish way to accomplish this, or is IS_NOT_IN_DB > not supposed to display a dropdown? From my reading of the > documentation, I thought it was supposed to do so.
