>From an under-the-hood perspective, this works because the Update function
probably looks something like:
int Update<T>(this IQueryable<T> query, Expression<Func<T,T>>
updateExpression);
Notice that the 2nd param there is an instance of an Expression class, not
a delegate. Because Expressions are a data structure not executable code
its possible to walk over them and use that inspection to generate the
update statement. The update function works because only the members we
want to update will be emitted in the expression tree.
On Thursday, January 8, 2015 11:22:53 AM UTC-5, Gunnar Liljas wrote:
>
> Hi Thierry,
>
> That's not a problem. Only the properties/columns included in the member
> initialization will be included in the update query, i.e
>
> session.Query<Animal>()
> .Where(x=>x.Age>3)
> .Update(x => new Animal {
> Name = "Peter",
> Age = x.Age+1,
> });
>
> will result in
>
> update Animal set Name='Peter',Age=Age+1
>
> 2015-01-07 23:01 GMT+01:00 Thierry Lach <thierr...@gmail.com <javascript:>
> >:
>
>> Sorry about coming late to the party, but if you use
>>
>> session.Query<Animal>()
>> .Where(x=>x.Age>3)
>> .Update(x => new Animal {
>> Name = "Peter",
>> Age = x.Age+1,
>> });
>>
>> how will you be able to tell when a field needs to be set to null, as the
>> default of an uninitialized field would also be null?
>>
>> I also don't see how you could recognize that a non-nullable numeric
>> field was _not_ being updated, as in:
>>
>> session.Query<Animal>()
>> .Where(x=>x.Age>3)
>> .Update(x => new Animal {
>> Name = "Peter",
>> });
>>
>>
>>
>>
>> On Thu, Jan 1, 2015 at 11:17 AM, Gunnar Liljas <gunnar...@gmail.com
>> <javascript:>> wrote:
>>
>>> https://github.com/nhibernate/nhibernate-core/pull/391
>>>
>>> 2014-12-19 17:46 GMT+01:00 Patrick Earl <hyn...@gmail.com <javascript:>>
>>> :
>>>
>>>> In our shop we use interfaces for entities exclusively since we have a
>>>> system that allows for complex inheritance. It would be sad to not have
>>>> support for interfaces or limited constructor scenarios.
>>>>
>>>> What's at the heart the statement that executes? If it's just a matter
>>>> of setting individual columns perhaps the syntax should reflect that more
>>>> than pretending like your C# constructor code is going to be called. Doing
>>>> it on individual properties allows for interfaces, doesn't incorrectly
>>>> imply that C# code is going to run on insert, and doesn't require the
>>>> availability of an empty public constructor on a concrete type.
>>>>
>>>> Patrick Earl
>>>> On Dec 18, 2014 6:02 PM, "Gunnar Liljas" <gunnar...@gmail.com
>>>> <javascript:>> wrote:
>>>>
>>>>> Yes...
>>>>>
>>>>> session.Query<Animal>()
>>>>> .Where(x=>x.Age>3)
>>>>> .Update(x => new Animal {
>>>>> Name = "Peter",
>>>>> Age = x.Age+1,
>>>>> });
>>>>>
>>>>> would work! Didn't think of that.
>>>>>
>>>>> I'm not completely sold on the "new Animal" part in an update. It
>>>>> looks linguistically wrong. But it's certainly less verbose. The same
>>>>> problems as for the Insert also applies.
>>>>>
>>>>> /G
>>>>>
>>>>>
>>>>> 2014-12-19 1:54 GMT+01:00 Alexander Zaytsev <haz...@gmail.com
>>>>> <javascript:>>:
>>>>>>
>>>>>> What about this:
>>>>>>
>>>>>> session.Query<Animal>()
>>>>>> .Where(x=>x.Age>3)
>>>>>> .Update(x => new Animal {
>>>>>> y.Name = "Peter",
>>>>>> y.Age = y.Age+1,
>>>>>> });
>>>>>>
>>>>>> ?
>>>>>>
>>>>>> On Fri, Dec 19, 2014 at 1:28 PM, Gunnar Liljas <gunnar...@gmail.com
>>>>>> <javascript:>> wrote:
>>>>>>>
>>>>>>> Absolutely possible, but the (big) difference is that
>>>>>>>
>>>>>>> 1. An anonymous object will lose the static type relationship with
>>>>>>> what you're updating/inserting, which kind of defeats the point of Linq
>>>>>>> bulk operations.
>>>>>>> 2. You will lose the possibility to express anything but simple
>>>>>>> value expressions, i.e "SET FullName = FirstName + ' ' + LastName" (
>>>>>>> Set(x=>x.FullName,x=>x.FirstName + " " + x.LastName), will not be
>>>>>>> possible.
>>>>>>>
>>>>>>> /G
>>>>>>>
>>>>>>> 2014-12-19 1:20 GMT+01:00 Craig van Nieuwkerk <cra...@gmail.com
>>>>>>> <javascript:>>:
>>>>>>>>
>>>>>>>> Looks nice. But yes, I think if you can have anonymous object for
>>>>>>>> the parameters this would be better. I have used FluentMigrator and it
>>>>>>>> does
>>>>>>>> this for Update/Insert pretty nicely.
>>>>>>>>
>>>>>>>> On Fri, Dec 19, 2014 at 11:13 AM, Alexander Zaytsev <
>>>>>>>> haz...@gmail.com <javascript:>> wrote:
>>>>>>>>>
>>>>>>>>> Very nice. I would like to remove word "All" from the
>>>>>>>>> operations.Also why do we need "Set" in update statement?
>>>>>>>>>
>>>>>>>>> On Fri, Dec 19, 2014 at 1:04 PM, Ricardo Peres <rjp...@gmail.com
>>>>>>>>> <javascript:>> wrote:
>>>>>>>>>>
>>>>>>>>>> Very nice! I implemented strongly typed delete in NH-3488
>>>>>>>>>> <https://nhibernate.jira.com/browse/NH-3488>, but the syntax was
>>>>>>>>>> a bit different:
>>>>>>>>>>
>>>>>>>>>> session.Delete<Product>(x => x.Price > 100);
>>>>>>>>>>
>>>>>>>>>> Do you have a pull request waiting to be issued?
>>>>>>>>>>
>>>>>>>>>> RP
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Thursday, December 18, 2014 11:21:06 PM UTC, Gunnar Liljas
>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>> So, now I have completed and old abandoned NH project, to create
>>>>>>>>>>> a Linq implementation of the bulk functionality. It's complete in
>>>>>>>>>>> the sense
>>>>>>>>>>> that all the unit tests from the HQL implementation passes with the
>>>>>>>>>>> Linq
>>>>>>>>>>> implementation as well, plus a couple more. Before I clean things
>>>>>>>>>>> up, I'd
>>>>>>>>>>> like you input on the syntax.
>>>>>>>>>>>
>>>>>>>>>>> Currently it works like this:
>>>>>>>>>>>
>>>>>>>>>>> Delete
>>>>>>>>>>>
>>>>>>>>>>> session.Query<Animal>()
>>>>>>>>>>> .Where(x=>x.Age>3)
>>>>>>>>>>> .DeleteAll();
>>>>>>>>>>>
>>>>>>>>>>> //all methods returns int (affected rows)
>>>>>>>>>>>
>>>>>>>>>>> Update
>>>>>>>>>>>
>>>>>>>>>>> session.Query<Animal>()
>>>>>>>>>>> .Where(x=>x.Age>3)
>>>>>>>>>>> .UpdateAll(x=>x
>>>>>>>>>>> .Set(y=>y.Name,"Peter")
>>>>>>>>>>> .Set(y=>y.Age,y=>y.Age+1)
>>>>>>>>>>> )
>>>>>>>>>>>
>>>>>>>>>>> Insert (i.e INSERT SELECT)
>>>>>>>>>>>
>>>>>>>>>>> session.Query<Animal>()
>>>>>>>>>>> .Where(x=>x.Age>3)
>>>>>>>>>>> .InsertInto(x=>new Human{
>>>>>>>>>>> Name=x.Name,
>>>>>>>>>>> Age=x.Name+10
>>>>>>>>>>> })
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> The Delete method was first implemented as
>>>>>>>>>>> session.Delete<Animal>(x=>x.Age>3), but I added the
>>>>>>>>>>> IQueryable<T>.DeleteAll extension for consistency.
>>>>>>>>>>>
>>>>>>>>>>> I welcome any ideas on how this can be improved/changed.
>>>>>>>>>>>
>>>>>>>>>>> /G
>>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>>
>>>>>>>>>> ---
>>>>>>>>>> You received this message because you are subscribed to the
>>>>>>>>>> Google Groups "nhibernate-development" group.
>>>>>>>>>> To unsubscribe from this group and stop receiving emails from it,
>>>>>>>>>> send an email to
>>>>>>>>>> nhibernate-development+unsubscr...@googlegroups.com <javascript:>
>>>>>>>>>> .
>>>>>>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>>>>>>
>>>>>>>>> --
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>> You received this message because you are subscribed to the Google
>>>>>>>>> Groups "nhibernate-development" group.
>>>>>>>>> To unsubscribe from this group and stop receiving emails from it,
>>>>>>>>> send an email to
>>>>>>>>> nhibernate-development+unsubscr...@googlegroups.com <javascript:>.
>>>>>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>>>>>
>>>>>>>> --
>>>>>>>>
>>>>>>>> ---
>>>>>>>> You received this message because you are subscribed to the Google
>>>>>>>> Groups "nhibernate-development" group.
>>>>>>>> To unsubscribe from this group and stop receiving emails from it,
>>>>>>>> send an email to
>>>>>>>> nhibernate-development+unsubscr...@googlegroups.com <javascript:>.
>>>>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>>>>
>>>>>>> --
>>>>>>>
>>>>>>> ---
>>>>>>> You received this message because you are subscribed to the Google
>>>>>>> Groups "nhibernate-development" group.
>>>>>>> To unsubscribe from this group and stop receiving emails from it,
>>>>>>> send an email to nhibernate-development+unsubscr...@googlegroups.com
>>>>>>> <javascript:>.
>>>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>>>
>>>>>> --
>>>>>>
>>>>>> ---
>>>>>> You received this message because you are subscribed to the Google
>>>>>> Groups "nhibernate-development" group.
>>>>>> To unsubscribe from this group and stop receiving emails from it,
>>>>>> send an email to nhibernate-development+unsubscr...@googlegroups.com
>>>>>> <javascript:>.
>>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>>
>>>>> --
>>>>>
>>>>> ---
>>>>> You received this message because you are subscribed to the Google
>>>>> Groups "nhibernate-development" group.
>>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>>> an email to nhibernate-development+unsubscr...@googlegroups.com
>>>>> <javascript:>.
>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>
>>>> --
>>>>
>>>> ---
>>>> You received this message because you are subscribed to the Google
>>>> Groups "nhibernate-development" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>> an email to nhibernate-development+unsubscr...@googlegroups.com
>>>> <javascript:>.
>>>> For more options, visit https://groups.google.com/d/optout.
>>>>
>>>
>>> --
>>>
>>> ---
>>> You received this message because you are subscribed to the Google
>>> Groups "nhibernate-development" group.
>>> To unsubscribe from this group and stop receiving emails from it, send
>>> an email to nhibernate-development+unsubscr...@googlegroups.com
>>> <javascript:>.
>>> For more options, visit https://groups.google.com/d/optout.
>>>
>>
>>
>>
>> --
>> ---
>> Facts do not cease to exist because they are ignored.
>> *Aldous Huxley*
>>
>> --
>>
>> ---
>> You received this message because you are subscribed to the Google Groups
>> "nhibernate-development" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to nhibernate-development+unsubscr...@googlegroups.com
>> <javascript:>.
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>
--
---
You received this message because you are subscribed to the Google Groups
"nhibernate-development" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to nhibernate-development+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
