[Lazarus] WebData

[Leonardo M. Ramé]

On 2010-10-16 12:18:30 +0200, Michael Van Canneyt wrote:
> 
> 
 >
> >I attached a proof of concept, take a look and comment.
> 
> Seems like a very good start, some suggestions:
> 
> 1. You created something which is by definition non-visual ?
>    Why not make the TDynamicSQLWebProvider a component which you can drop on a webmodule ?
> 
> 2. Having done 1, you could rework TModuleProvider so it recognizes and uses a TDynamicSQLWebProvider dropped on it.
>    (if I understand correctly, there is no need to do anything, it would be automatic if the
>     TDynamicSQLWebProvider uses it's owner as the owner for the providers)
> 
> 3. Why not create the providers on an as-needed basis ?
>    Now you create all registered providers.
>    If you override the GetProvider method in TModuleProvider, you can simply create the instance you actually need.
> 
>    My projects contain typically 1000+ providers.
>    If I would create them all in memory per connection - memory consumption would rocket sky high :-)
> 
>    I would simply load the definitions - once - and then create providers on an as-needed basis.
> 
> 4. You forgot the XMLprovider unit :-)
>    Seems like you make it a procedural interface to load the definitions.
>    I would expect that TSqlWebDataProviders has a virtual abstract method which loads the definitions from file:
>    Procedure LoadFromFile(Const AFileName : String); virtual; Abstract;
>    In the case of a component, there could even be a 'FileName' property, read in the 'Loaded' method.
>    then create a descendent which loads from whatever file format is fitting.
> 
> 5. Advanced concept:
>    Why didn't you use the TFPWebDataProviderManager factory class ? (see demo5)
> 
>    It is built for this kind of thing. (I currently use that at work) : you register all providers there.
>    TFPWebProviderDataModule knows about this class and fetches a provider there on-demand.
>    All you'd need to do is register 1 TModuleProvider instance there.  This is optional of course.
>    So in fact, there are 2 paths you could follow.
> 
> I hope all this makes sense :-)
> 
> Michael.

Thanks, I'll try to implement this next week.

-- 
Leonardo M. Ramé
http://leonardorame.blogspot.com