NHibernate is fine for dealing with this number of tables. Typically the
number of tables affects only two things:

- Design time support, if your ORM has a designer that shows all tables
Of course this is not the case with NHibernate. No designer! So, you should
not have the issue at all.
(BTW: This is a known major issue with other options like Entity Framework,
going near q00 tables makes designer performance go down, also, this is not
a problem in some professional 3rd party designer-like tools like LLBLGen,
and not an issue of course in LLBLGen ORM itself)

- Startup time: Reading the tables metadata in run-time when the application
starts
This will be your main issue I guess. It'll take quite sometime for the
application to start. (This is the step of creating configuration and
session factory I'm talking about, typically written in application start).
You can make it less harmful by caching the configuration (mapping, etc) and
loading from a cache file. There was another thread in the list talking
about that. This will save you a lot eveyr time you load from the cache, yet
when the configuration changes and the configuration needs to be built not
got from cache, it'll still take sometime.
(Yes, this is an issue also for Entity Framework, and not an issue for
LLBLGen ORM as it doesn't load this in runtime but generates it)

During application tasks like read and save etc, number of tables should not
count I think.


Regarding LINQ provider. It's fine I guess. I'm one of those using it in
production. Not everything is supported, but not worse than Entity Framework
LINQ provider itself I guess. You'll not find a 100% LINQ hero even from
Microsoft itself if you ask me.

--
*Mohamed Meligy*
Senior Developer, Microsoft Technologies - Technical Delivery Group
Injazat Data Systems
P.O. Box: 8230, Abu Dhabi, U.A.E. (*GMT+4*)**

Direct:     +971   2 4045385
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On Wed, Jul 14, 2010 at 5:23 AM, Diego Mijelshon <[email protected]>wrote:

> What is your question 1? What are your concerns? (I see no question marks
> there...)
>
> And 2... yes, the LINQ provider is working well, which doesn't mean it's
> perfect.
> I'm not a NH committer, but I'd recommend it without hesitation.
>
>     Diego
>
>
>
> On Tue, Jul 13, 2010 at 18:00, Max André Bündchen 
> <[email protected]>wrote:
>
>> That's my first post at nhusers! I found many older post about some of
>> my subjects but I can't get a conclusion by myself. The questions is
>> general, not detailed, but I hope I can get some tips from the
>> experienced users about a direction.
>>
>> My team is migrating a large project to .Net (large means we have
>> about 400 tables in the database splited in 12 integrated modules) and
>> we would like to use NHibernate + Linq (that's the reason to use the
>> trunk version) to manage data access instead of direct access and T-
>> SQL (the current not-.Net version works with T-SQL).
>>
>> My questions are about:
>>
>> 1. Performance in cases with huge meta-data/tables (I know, it depends
>> a lot of other things).
>> 2. There's many post in the group talking about the successful use of
>> the new Linq provider in production environments, but is it
>> recommended by the developers? The 2k+ unit tests used to verify the
>> trunk say yes. :)
>>
>> Sorry for some mistakes, but English is my third language. :(
>>
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