Ah, I get it. I didn't realize you could map fields in NHibernate. But since fields can't be virtual, how does that affect lazy-loading of the type?
~Dathan On May 14, 2:04 am, nadav s <[email protected]> wrote: > my suggestion was to map the field - then the field gets a null but the > public property returns the "NULL object". > same goes for the set of the public property - if it got the "Null object" > it puts actual null in the field > > > > > > On Thu, May 13, 2010 at 2:03 PM, John Davidson <[email protected]> wrote: > > You can create a base class for all your mapped objects with a must inherit > > requirement. That allows you to create a single implementation and then > > reuse it (DRY). > > > John Davidson > > > On Thu, May 13, 2010 at 3:25 AM, Dathan <[email protected]> wrote: > > >> That seem like it addresses the problem - because NHibernate reads the > >> value from the property when saving, if the internally-stored value is > >> null, the property will return my "NULL" value, and NHibernate will > >> attempt to serialize that to the DB, rather than the NULL value that I > >> actually want to store. > > >> It seems like a custom user type would fit the bill, because it > >> supports NullSafeGet and NullSafeSet methods (sorry if I'm misstating > >> the actual method names - the idea is right, though, right?). Using > >> that, I could override Equals() on each of my classes, and the > >> UserType for the class would do something like "if (! > >> obj.Equals(ObjectClassType.Null)) return obj else return null;". > >> Would that work? I'd prefer an approach that doesn't require me to > >> implement a custom UserType per model class, though, so if there are > >> any other options, I'm eager to hear them. > > >> Thanks! > > >> Dathan > > >> On May 7, 6:45 pm, nadav s <[email protected]> wrote: > >> > use a field that will get the data, and a property that in its get > >> method, > >> > checks if the field is null and if so, returns the default > > >> > On Sat, May 8, 2010 at 1:12 AM, Dathan <[email protected]> wrote: > >> > > Hi, all. > > >> > > I'm trying to strengthen my domain by eliminating null in favor of > >> > > "Null" objects with explicit semantics. E.g., > > >> > > class Category > >> > > { > >> > > private static Category @default; > > >> > > static Category() > >> > > { > >> > > // init @default here > >> > > } > > >> > > public virtual int ID { get; set; } > >> > > public virtual string Name { get; set; } > >> > > public virtual Category Parent { get; set; } > >> > > public static Category None { get { return @default; } } > >> > > } > > >> > > My categories support nesting (hence the Parent property), but top- > >> > > level categories won't have parents. I'd like to represent this in my > >> > > model by having the category's Parent set to Category.None. My > >> > > question is, in terms of NHibernate, what's the best way to map this? > >> > > Should I have a category record in my database called None with a null > >> > > ParentID, and have all "top-level categories" store that ID as their > >> > > parent? Or, should I serialize all references to Category.None as > >> > > NULL categoryID's, and replace all NULL CategoryID's with > >> > > Category.None upon retrieval? (If so, how?) What's the best practice > >> > > here? > > >> > > Thanks! > > >> > > ~Dathan > > >> > > -- > >> > > You received this message because you are subscribed to the Google > >> Groups > >> > > "nhusers" group. > >> > > To post to this group, send email to [email protected]. > >> > > To unsubscribe from this group, send email to > >> > > [email protected]<nhusers%[email protected] > >> > > > > >> <nhusers%[email protected]<nhusers%252bunsubscr...@googlegroup > >> s.com> > > >> > > . > >> > > For more options, visit this group at > >> > >http://groups.google.com/group/nhusers?hl=en. > > >> > -- > >> > You received this message because you are subscribed to the Google > >> Groups "nhusers" group. > >> > To post to this group, send email to [email protected]. > >> > To unsubscribe from this group, send email to > >> [email protected]<nhusers%[email protected] > >> > > >> . > >> > For more options, visit this group athttp:// > >> groups.google.com/group/nhusers?hl=en. > > >> -- > >> You received this message because you are subscribed to the Google Groups > >> "nhusers" group. > >> To post to this group, send email to [email protected]. > >> To unsubscribe from this group, send email to > >> [email protected]<nhusers%[email protected] > >> > > >> . > >> For more options, visit this group at > >>http://groups.google.com/group/nhusers?hl=en. > > > -- > > You received this message because you are subscribed to the Google Groups > > "nhusers" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]<nhusers%[email protected] > > > > > . > > For more options, visit this group at > >http://groups.google.com/group/nhusers?hl=en. > > -- > You received this message because you are subscribed to the Google Groups > "nhusers" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group > athttp://groups.google.com/group/nhusers?hl=en. -- You received this message because you are subscribed to the Google Groups "nhusers" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nhusers?hl=en.
