Use can, obviously, use projections and only fetch the properties you are
interested in. Something like;
var products = Session.Query<Product>().Select(p => new {
p.Id, CategoryName = p.Category.Name <http://p.category.name/> }).ToList();
On Wednesday, March 15, 2017 at 12:35:16 PM UTC, Felipe Oriani wrote:
>
> Hey guys, I am looking at the problem for "select n+1" queries. It scare
> us when I a session with more than 10 queries more than 100 in some cases
> haha). Some refactoring to do.
>
> Sometimes I just need a string property to fill a column on the grid and
> using `Fetch` extension method NHibernate fill the entire entity on the
> relation.* Is there any way to tell to NHibernate fill up just a column I
> need, without using the `Select` (from Linq) or `SelectLitst` (from
> QueryOver)?* Something like this:
>
> var products = Session.Query<Product>().FetchProperty(p => p.Category.Name
> ).ToList();
>
> @Nestor, these cases are not huge tables. it will not pass more than 1000
> records and some filters applied.
>
> Thank you Guys
>
>
> On Wed, Mar 15, 2017 at 5:15 AM, Nestor Andres Rodriguez <
> nest...@gmail.com <javascript:>> wrote:
>
>> Hi Felipe,
>>
>> Joins may be expensive. But what is really important prior to any
>> optimization is to know how the data in this query behaves (reads, writes),
>> how often this query will be executed, how important is this query for the
>> business and customers, would it be a problem if it takes a few minutes ,
>> how up-to-date should be the information, seconds, minutes, hours.
>>
>> If this query needs for example to be executed in few milliseconds, and
>> you have million of records on each of the 6 tables then probably you
>> would like to avoid calculating the joins every time, so you may create a
>> denormalised table which is updated regularly using some triggering
>> mechanism, the downside is that you have to maintain yet another table and
>> a trigger mechanism.
>>
>> At the end everything has a cost, and you need to identify if it worth
>> it. If nobody complains and you do not see a good reason to optimize it,
>> just do not care about that.
>>
>> Cheers,
>> Nestor
>>
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>
>
> --
> ______________________________________
> Felipe B Oriani
> felipe...@gmail.com <javascript:>
>
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