Could you please comment on limitations of memory provider vs SQL Server provider?

I would like unit tests to be performed using memory provider, because I can recreate the domain in the [SetUpFixture]... and begin and rollback a transaction in [SetUp] and [TearDown] methods... to give me clean isolated state in each test.

Obviously, the production environment will run with SQL Server provider instead.

Also, what's going on with the blog posts? The glory days were when you'd blog roughly each day.Your blog is #1 on my RSS reader... and I imagine many of your customers would like to hear frequent updates.

Updated at 22.01.2010 1:13:49

With the DisconnectedState release, will we see a BindingSource component to use in Windows Forms? Will we also see a best practices sample application? When is this expected to be released?

I am really eager to upgrade our 3.9 (WinForms) project to 4.0. It would be nice to have a document detailing some of the important issues during the upgrade process (both model and database [SQL Server]).

Also, when can we expect to use a Silverlight client with DO4? I've read about the O2O mapper you've proposed. How far away do you think this is?

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asked Jan 20 '10 at 23:12

ara's gravatar image


One Answer:

In-memory provider:

  • Can't persist changes between application restarts

  • Does not support nested transactions

  • Does not support concurrent transactions (it actually serializes them)

  • Does not support rollback at all so far

  • May execute complex queries slower, because the optimizer we have now performs only very basic optimizations (index usage).

So that's are the limitations. Many of them will be resolved when we'll switch back to development of our own providers - likely, this will happen after v4.2 release.

Concerning blog: true, I blogged almost nothing during last month. Basically, that's because:

  • There were family-related issues. Nothing really serious, but it took a lot of time (likely, ~ 2 weeks at all; there were NY holidays in Russia, but this wasn't enough).

  • I feel myself quite uncomfortable because of continuing delay with v4.1, so all the efforts I apply mainly related to DO4 itself & Manual - features I must get finished ASAP.

So my short-time plan is: 1) DO4 Manual: wrong spaces in code, epilogue, Legacy upgrade mode, locking, versions, particular usage scenarios (ASP.NET, etc.), final PDF. 2) DO4 Installer: no more .PDB, single help file. 3) DO4 itself: CoreServices -> ProtectedServices, DomainConfiguration.Types refactoring, expose low-level objects like DbConnection 4) Release 4.1

Next is goal is v4.1.1, I should review & refactor (a bit) DisconnectedState, add the documentation and release it.

v4.2 is in development now - all the other team members work on it.

> ... will we see a BindingSource component to use in Windows Forms?

So far we're thinking mainly about WPF. We don't have any exact plans on WindowsForms implementation right now, but I know that some of interfaces used there are required by WPF as well. So I suspect I'll be able to provide more precise answer only closer to release of v4.1.1.

> Will we also see a best practices sample application?

For WPF - definitely. We already have a prototype of it: OrderAccounting sample.

For WindowsForms - definitely, if the decision to support it will be made.

> When is this expected to be released?

v4.1.1 will be available in the beginning of February, but it will fully support just WPF. Quality\level of WindowsForms support is under the question - we're ready to spend the time on evaluation of possible approaches there, but I fear we must not delay this release because of this feature. If it will be obvious there is nothing really complex, we'll add all support for WindowsForms as ~ v4.2.X update (plans for v4.2 are also fixed now).

So in the best case basic WindowsForms support can be expected closer to the end of February.

> ... when can we expect to use a Silverlight client with DO4? I've read about the O2O mapper you've proposed. How far away do you think this is?

O2O mapper is part of v4.2, which is currently planned for February. AFAIK all the basic stuff already works there, but currently there is no LINQ rewriter for it.

answered Jan 21 '10 at 10:22

Alex%20Yakunin's gravatar image

Alex Yakunin

Forgot to add: you may find I already restarted my blogging activity today ;)

(Jan 21 '10 at 10:22) Alex Yakunin Alex%20Yakunin's gravatar image
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