May 2005 - Posts

How/Why I Added a Wiki for WilsonDotNet

I've had several users of my ORMapper and UIMapper suggest that I add a Wiki to WilsonDotNet -- and I agreed it was a good idea.  My first problem was finding the time to setup a Wiki, since I'm typically pretty busy already with my work and other projects.  Of course this shouldn't be a big deal I was told since there are already some really good Wikis freely available, like FlexWiki.  So a while back I downloaded FlexWiki and proceeded to setup a simple test Wiki on my local system -- took about an hour or so.  At this point I was convinced that this would work out, but I still needed to integrate the Wiki with the rest of my existing site.

And this is where things started to go downhill.  First I wanted to allow anonymous users to read my Wiki, but I only wanted my existing subscribers to be able to edit and create topics -- yes, this isn't a "pure" Wiki concept, but its what I wanted to do.  I proceeded to look through the documentation and I found that this was something that others had also requested -- and failed.  I did more searches and again found more people wanting this type of feature, but it just isn't supported out of the box so far.  Of course you can always modify the app yourself, since its open-source, but I discovered that the codebase is quite involved.

At this point I thought I would just try some modifications to the web.config file in the authentication/authorization sections.  Surely this wouldn't be too hard, but things didn't work out so easily -- I think because the Wiki needed to be its own IIS app.  So now I decided to just give up and try it on my real site, again since I don't have a lot of time to waste getting this to work.  This resulted in discovering that you can't just create your Wiki locally and simply upload and expect the links to work correctly.  Another search showed that I wasn't alone in finding this to be an issue -- and there doesn't appear to be any solution to this.

At this point I had certainly put in more than a couple of hours, although I didn't track it to say it was 4, 8, or more hours.  So I tabled this whole Wiki thing for a good while, and then recently I decided to think about this Wiki thing in another way.  What is a Wiki?  Its a set of topics, viewable as formatted Html, which can be edited and/or created, and a history is kept too.  If you think about it that way, a Wiki does not sound very hard at all -- especially if you use the FreeTextBox for Html edits.  So I did it -- in 30 minutes at most!  And in my opinion its far better, at least for me, since it integrates with my site too.

So there you have it.  I have my own Wiki that fits seamlessly into my already existing site and ties into my existing set of users.  Its also far easier to use for someone like myself that isn't up on all the special codes needed to edit/create the formatted Html because I'm just letting my users have the full power of the FreeTextBox -- maybe this isn't a "real" Wiki, but its better for me.  I also maintain a complete history of all edits, although I haven't exposed this yet (if ever), which I do think is a good idea.  And I got all of this up and running in no time at all -- far less when compared with trying to figure out an existing free Wiki.
Posted by PaulWilson | 4 comment(s)

Check out my "Real" NHibernate Example App

As most of you know that follow my blog, I not only have my own WilsonORMapper, but I've also been tinkering with NHibernate some.  Why?  I needed to use a "free" set of code for my recent presentation on O/R Mapping at the Atlanta Code Camp.  Anyhow, here's the long promised link to download my "real" NHibernate example app.  What do I mean by calling it "real"?  Well to put it bluntly, my experience is that its impossible to find a realistic and decently complex app for NHibernate (or Hibernate).  My example app is the exact same one I updated for my WilsonORMapper, except I modified it slightly to support NHibernate.  This means that it is first of all a real and fully functioning WinForm app -- complete with data-binding in grids and all your basic CRUD.  It also means that this example includes several types of primary keys, relationships, and inheritance -- and did I mention it works!

Sure there is lots of documentation for Hibernate (and thus for NHibernate too), including books, but the examples are either typically small snippets, and many are outdated and just don't work with NHibernate v0.8.  Some people have criticized the small amount of documentation I have for my WilsonORMapper, and rightly so, but I've always included a real example app that goes a long way in getting people started -- and without this I found it quite difficult to get up to speed on NHibernate since I was forced to dig into scattered documents, forums, and just plain old-fashioned trial-and-error in many cases!  Here's an example -- NHibernate has multiple ways to model related collections (sets, bags, lists, and maps), which certainly is an advantage if you need flexibility, but just try to figure out which one to use for a many-to-many related collection that you want to be bindable -- the answer is use the bag.

Anyhow, what's intriguing to me is how close both the basic approach and the mapping file syntax is for my WilsonORMapper and NHibernate -- they are remarkably similar and there's very little effort to switch between them.  Of course there are certainly differences too -- NHibernate is more flexible if you need that (most don't), while my WilsonORMapper is a little easier (far simpler codebase), supports more databases (including Access), and provides DAL capabilities as well as O/R Mapping.  Both mappers have features the other lacks -- but they both have the basic set of features that most people need -- and both work as my example apps demonstrate.  What are some other features my WilsonORMapper has?  Supports stored procedures, custom collection types, real batch updates/deletes, server-side paging, lazy-loading without keeping "session" open, interface to avoid reflection, null values even in .NET v1.1, and I'm sure there are others I could list.

What about NHibernate you ask?  I can't do it much justice to be fair since I'm not that experienced with it, but a few come to mind: more caching options, normalized inheritance, built-in one-to-one, two-way graph syncs, more cascade options, eager load option -- and again there are bound to be more.  But the basics are pretty similar (although I prefer my WilsonORMapper of course) -- so if you're an NHibernate fan, then please download and enjoy my "real" NHiberate example app -- and feel free to add your own comments here on either mapper (or others), although please include some real details if you do.

WilsonORMapper v4.0 Released -- Includes .NET v2.0 Generics and Nullable Types

My WilsonORMapper v4.0 has finally been released out of beta with support for another database inheritance type,
as well as .NET v2.0 support for generics and nullable types -- and even more OPath support thanks to Jeff Lanning.
Download the updated demo package which contains both the usual simple demo and a more complex example.

Update: WilsonORMapper v4.0.0.0 (5/26/2005) includes the following:
  • Supports "shared inheritance" in the database using type discriminator.
  • This is also referred to as "single table with type discriminator".
  • Always supported "redundant inheritance" or "one table per concrete type".
  • Added support for .NET v2.0 Generics and Nullable Types -- VS 2005 Beta.
  • Allows you to initialize you own relation collections, as long as IList.
  • Works for all new objects, as well as non-lazy cases for existing objects.
  • QueryHelper GetExpression expanded with ComparisonOperators by Paul Welter.
  • Also includes nearly complete OPath engine (Longhorn Specs) by Jeff Lanning.
  • Added ExecuteScalar and GetDataSet methods to the Transaction class.
  • Added defaultNamespace for types that do not include the Namespace.
  • Breaking Change: ExecuteCommand/Update/Delete returns int (not bool).
  • Bug Fixes: Enum support, ObjectSet indexer, two types with the same name.
  • Bug Fixes: Exceptions and Parameter are now marked Serializable also.
  • And a special thanks to Jeff Lanning for help with both OPath and Generics.
Posted by PaulWilson | 6 comment(s)

Wally McClure Releases .NET PodCast -- Guess Who is Interviewed

Wally McClure has released his first .NET PodCast -- including lots of good SQL 2005 stuff from Wally.  Oh yea, he's also interviewed me for this PodCast -- although I wish my allergies hadn't been so bad since I sound terrible.
Posted by PaulWilson | 5 comment(s)

Preparing for the Atlanta Code Camp

I'm scheduled first thing in the morning to present an "Introduction to O/R Mapping" at the Atlanta Code Camp.  I've given many presentations to my teams in the past, but this will be my first public presentation -- so wish me the best.  Will I make a good trainer -- or should I stick to designing and implementing solutions for clients -- we'll find out tomorrow.  :)  Of course, as luck would have it, my allergies are acting up in a major way yesterday and today -- just like every May -- so hopefully I'll feel better.  By the way, since code camps are supposed to be free code only, I'll be using NHibernate for my set of examples -- I've actually got a nice little reference app with both an NHibernate implementation and a WilsonORMapper implementation.  It demos just about every type of relationship and key type, as well as making use of a lot of inheritance (supported in v4.0 of my mapper, currently in beta).  I'll post both versions in the coming week or so, when mine gets out of beta -- I think the NHibernate crowd will appreciate it since I've failed to find a good example app in my search.  Maybe I'll also share some of my experiences working with NHibernate, which isn't bad at all -- of course I still like mine better.  :)  Finally, for all those who have asked, I've added a Wiki to my WilsonDotNet site where anyone can view it but only subscribers can edit it -- maybe I'll share some information about why I did it the way I have soon also.
Posted by PaulWilson | 5 comment(s)

Nullable Types are NOT Integrated in .NET v2.0

Nullable value types have been added to .NET v2.0, but they have NOT really been integrated.  The C# team has done a good job incorporating support for nullable types into the syntax, but the VB team has done nothing, which once again leaves VB behind the curve in features.  But that is not what this post is about -- this post is about the fact that nullable types have NOT been integrated into the rest of the .NET framework -- and obvious places at that.

(1) Reading Data: Given a data reader, you can't just assign a value to a nullable type!  This one just seems incomprehensible -- nullables obviously already exist in the database, and the .NET SqlTypes support them already, so this seems to be a key integration point.  But alas, you simply can NOT assign a value from your data reader to a nullable type.  Instead, you still have to explicitly test for DBNull, and handle that case separately:
 
    int? nullInt;
    if (dataReader.IsDBNull(index)) { nullInt = null; }
    else { nullInt = dataReader.GetInt32(index); }

Note that Julia Lerman observed this before -- see her comments for more viewpoints.

(2) ConvertType: C# does at least support casts to/from regular types and nullable types, and it even gives you a handy way to convert nulls to a default by using the ?? operator, but just try to do any generic type conversions with Convert.ChangeType -- not supported!  Again this seems like an obvious integration point, if nullable types are to be "builtin", but once again the new nullable types just feel like an afterthought -- and NOT integrated.

(3) WinForm Controls: The official story is that the data grids support nullable types, but what happens when you try to use a NumericUpDown or a DateTimePicker -- not supported!  That's right, once again you'll find that you still have no real integration for nulls, and you'll have to continue resorting to magic values or checkboxes and manual conversions.  These controls seem like another obvious place where there should be support for nullables.

All of this lack of integration makes me wonder what the point of nullable types really is?  We could always create our own structs that supported the concept of null very similarly, but they lacked the builtin syntax support that C# is including, not to mention they failed to work with data-binding in grids, but the new nullable types simply aren't much better.  The one thing they have going for them is that they will at least be a "standard" nullable.

Note that none of these issues prevented me from adding support for nullable types to my O/R Mapper, but I just thought I'd pass along what I observed since I do think the support I discovered was very disappointing.
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