Comments on: Build Your Own Data Access Layer: Lazy Loading http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/ Trying to walk that thin line between intelligence and ignorance Thu, 09 Sep 2010 13:37:05 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Davy Brion http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-24789 Davy Brion Wed, 13 Jan 2010 09:45:21 +0000 http://davybrion.com/blog/?p=1528#comment-24789 @Nagarajan the session is explained in this post: http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-bringing-it-all-together/ @Nagarajan

the session is explained in this post:
http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-bringing-it-all-together/

]]> By: Nagarajan http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-24774 Nagarajan Wed, 13 Jan 2010 08:17:30 +0000 http://davybrion.com/blog/?p=1528#comment-24774 Hi, In class EntityHydrater, there is a method called CreateProxy and it uses "session" object in LazyLoadingInterceptor. where it comes from?. Regards, Nagarajan. Hi,

In class EntityHydrater, there is a method called CreateProxy and it uses “session” object in LazyLoadingInterceptor. where it comes from?.

Regards,
Nagarajan.

]]> By: Davy Brion http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22669 Davy Brion Thu, 08 Oct 2009 13:00:25 +0000 http://davybrion.com/blog/?p=1528#comment-22669 it hasn't been deployed in production yet, but so far we haven't had problems with it i'm sure some problems will come up sooner or later though :p it hasn’t been deployed in production yet, but so far we haven’t had problems with it

i’m sure some problems will come up sooner or later though :p

]]> By: Gareth http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22668 Gareth Thu, 08 Oct 2009 12:54:05 +0000 http://davybrion.com/blog/?p=1528#comment-22668 Often the best reason I find ;) I'm building something using a similar model and was concerned in case there were issues accessing the attributes in that scenario. BTW how is the code behaving in the wild? Often the best reason I find ;)

I’m building something using a similar model and was concerned in case there were issues accessing the attributes in that scenario.

BTW how is the code behaving in the wild?

]]> By: Davy Brion http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22667 Davy Brion Thu, 08 Oct 2009 11:26:32 +0000 http://davybrion.com/blog/?p=1528#comment-22667 not really a specific reason for that, other than that was the first thing that came to my mind ;) not really a specific reason for that, other than that was the first thing that came to my mind ;)

]]> By: Gareth http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22666 Gareth Thu, 08 Oct 2009 10:34:27 +0000 http://davybrion.com/blog/?p=1528#comment-22666 Great series of posts Davy! Question regarding the LazyLoadingInterceptor - is there a specific reason why you check for the primary key using the property name rather than looking for the primary key attribute on the invocation method? Gareth Great series of posts Davy!

Question regarding the LazyLoadingInterceptor – is there a specific reason why you check for the primary key using the property name rather than looking for the primary key attribute on the invocation method?

Gareth

]]> By: Krzysztof Koźmic http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22362 Krzysztof Koźmic Fri, 28 Aug 2009 12:08:58 +0000 http://davybrion.com/blog/?p=1528#comment-22362 Davy, from the DP perspective, you could clean things up a little bit (and get some performance improvement) if you used IProxyGenerationHook and/or IInterceptorSelector to control which members to override/intercept. Krzysztof Davy,

from the DP perspective, you could clean things up a little bit (and get some performance improvement) if you used IProxyGenerationHook and/or IInterceptorSelector to control which members to override/intercept.

Krzysztof

]]> By: kilfour http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22361 kilfour Fri, 28 Aug 2009 11:25:07 +0000 http://davybrion.com/blog/?p=1528#comment-22361 Most custom DAL's are something that have me waking up screaming in the middle of the night, during the period I'm confronted with them. Still a lot of developers insist on writing one, instead of using a mature solution that's allready out there. Great job with this one though, and an even better job of putting the effort into perspective. Just one of many examples why you better not write your own DAL, and if you do, sit down and think about it first. Introducing a new concept Immutable Lazy Loading : <code> public Product.Product Product { get { if (_Product == null) { _Product = DAOFactory.ProductFactory.RetrieveProductByProductID(ProductID); } else { if (!(_Product.Id.Equals(ProductID))) { _Product = DAOFactory.ProductFactory.RetrieveProductByProductID(ProductID); } } return _Product; } set { _Product = value; } } </code> Millions more where that came from. Most custom DAL’s are something that have me waking up screaming in the middle of the night, during the period I’m confronted with them. Still a lot of developers insist on writing one, instead of using a mature solution that’s allready out there. Great job with this one though, and an even better job of putting the effort into perspective.
Just one of many examples why you better not write your own DAL, and if you do, sit down and think about it first.
Introducing a new concept Immutable Lazy Loading :

public Product.Product Product
{
get
{
if (_Product == null)
{
_Product = DAOFactory.ProductFactory.RetrieveProductByProductID(ProductID);
}
else
{
if (!(_Product.Id.Equals(ProductID)))
{
_Product = DAOFactory.ProductFactory.RetrieveProductByProductID(ProductID);
}
}
return _Product;
}
set
{
_Product = value;
}
}

Millions more where that came from.

]]> By: Steve http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22360 Steve Fri, 28 Aug 2009 11:21:17 +0000 http://davybrion.com/blog/?p=1528#comment-22360 Thanks. I'm looking forward to Session and UnitOfWork :) Thanks. I’m looking forward to Session and UnitOfWork :)

]]> By: Reflective Perspective - Chris Alcock » The Morning Brew #422 http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22359 Reflective Perspective - Chris Alcock » The Morning Brew #422 Fri, 28 Aug 2009 07:34:57 +0000 http://davybrion.com/blog/?p=1528#comment-22359 [...] Build Your Own Data Access Layer: Lazy Loading - Davy Brion continues his series of posts on building a custom DAL, looking at how Lazy Load of entities can be achived. In A guide into OR/M implementation challenges: Lazy loading Ayende follows on from Davy’s post with a look at how NHibernate handles the Lazy Load [...] [...] Build Your Own Data Access Layer: Lazy Loading – Davy Brion continues his series of posts on building a custom DAL, looking at how Lazy Load of entities can be achived. In A guide into OR/M implementation challenges: Lazy loading Ayende follows on from Davy’s post with a look at how NHibernate handles the Lazy Load [...]

]]> By: Davy Brion http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22358 Davy Brion Thu, 27 Aug 2009 21:02:06 +0000 http://davybrion.com/blog/?p=1528#comment-22358 that's a good question... i certainly wouldn't try to write a proxy generator, that's for sure :P if i wasn't allowed to use DynamicProxy in this DAL, i'd probably try to enable lazy-loading by wrapping reference properties in something which only provides a .Value property and do the lazy loading when the Value property is accessed (like how IFutureValue in NHibernate works). The only way to access the reference property would be through the Value property so the calling code would be oblivious to the fact, though it would be uglier than just using a property. you'd basically get something like invoice.Customer.Value in your code, instead of just invoice.Customer that’s a good question… i certainly wouldn’t try to write a proxy generator, that’s for sure :P

if i wasn’t allowed to use DynamicProxy in this DAL, i’d probably try to enable lazy-loading by wrapping reference properties in something which only provides a .Value property and do the lazy loading when the Value property is accessed (like how IFutureValue in NHibernate works). The only way to access the reference property would be through the Value property so the calling code would be oblivious to the fact, though it would be uglier than just using a property.

you’d basically get something like invoice.Customer.Value in your code, instead of just invoice.Customer

]]> By: Bertrand Le Roy http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22357 Bertrand Le Roy Thu, 27 Aug 2009 20:55:12 +0000 http://davybrion.com/blog/?p=1528#comment-22357 I was going to say the same thing as Ryan but he beat me to it. Thanks to your answer I understand why Castle is OK on that specific project, but what would you do if it wasn't and if the constraint was no external dependencies at all? I was going to say the same thing as Ryan but he beat me to it. Thanks to your answer I understand why Castle is OK on that specific project, but what would you do if it wasn’t and if the constraint was no external dependencies at all?

]]> By: Davy Brion http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22355 Davy Brion Thu, 27 Aug 2009 18:36:05 +0000 http://davybrion.com/blog/?p=1528#comment-22355 I think their biggest fear is simply that of not being able to 'change' things in case something doesn't work. We've suggested NHibernate, Linq To SQL, Entity Framework, ... you name it. They didn't want any of it... the only thing they have no problem with is either stored procedures, or straight ADO.NET. The fact that this DAL is somewhat reminiscent of NHibernate (in terms of usage, not in terms of features) is either something they won't even realize, or won't even care about because the code is right there and it's easy to modify in case things 'go wrong'. I'm not even gonna get into their realistic abilities when it comes to changing things for the better, but that is unfortunately their attitude. And it's only when it comes to data access. We can use Windsor, we can use DynamicProxy, we can use the Request/Response service layer... they don't care about any of that. I've been having discussions like that for about a year now, and after a while i simply stopped caring. It's their problem and if they're willing to pay the extra cost that comes with such a mindset, then so be it. But repetitive and error-prone data-access code is something i can't stand, whether you write it manually or even if it's generated... that's why i finally wrote this :) I think their biggest fear is simply that of not being able to ‘change’ things in case something doesn’t work. We’ve suggested NHibernate, Linq To SQL, Entity Framework, … you name it. They didn’t want any of it… the only thing they have no problem with is either stored procedures, or straight ADO.NET.

The fact that this DAL is somewhat reminiscent of NHibernate (in terms of usage, not in terms of features) is either something they won’t even realize, or won’t even care about because the code is right there and it’s easy to modify in case things ‘go wrong’.

I’m not even gonna get into their realistic abilities when it comes to changing things for the better, but that is unfortunately their attitude. And it’s only when it comes to data access. We can use Windsor, we can use DynamicProxy, we can use the Request/Response service layer… they don’t care about any of that.

I’ve been having discussions like that for about a year now, and after a while i simply stopped caring. It’s their problem and if they’re willing to pay the extra cost that comes with such a mindset, then so be it. But repetitive and error-prone data-access code is something i can’t stand, whether you write it manually or even if it’s generated… that’s why i finally wrote this :)

]]> By: Ryan Scott http://davybrion.com/blog/2009/08/build-your-own-data-access-layer-lazy-loading/comment-page-1/#comment-22354 Ryan Scott Thu, 27 Aug 2009 18:10:59 +0000 http://davybrion.com/blog/?p=1528#comment-22354 Davy, I thought the reason you were building a custom DAL was to circumvent NIH attitudes. Doesn't using DynamicProxy raise the same concerns? Or are they only concerned with owning/writing the DAL as a whole? Davy, I thought the reason you were building a custom DAL was to circumvent NIH attitudes. Doesn’t using DynamicProxy raise the same concerns? Or are they only concerned with owning/writing the DAL as a whole?

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