Translating Where() to sql
- by MBoros
Hi.
I saw DamienG's article (http://damieng.com/blog/2009/06/24/client-side-properties-and-any-remote-linq-provider) in how to map client properties to sql.
i ran throgh this article, and i saw great potential in it. Definitely mapping client properties to SQL is an awesome idea.
But i wanted to use this for something a bit more complicated then just concatenating strings. Atm we are trying to introduce multilinguality to our Business objects, and i hoped we could leave all the existing linq2sql queries intact, and just change the code of the multilingual properties, so they would actually return the given property in the CurrentUICulture.
The first idea was to change these fields to XMLs, and then try the Object.Property.Elements().Where(...), but it got stuck on the Elements(), as it couldnt translate it to sql. I read somewhere that XML fields are actually regarded as strings, and only on the app server they become XElements, so this way the filtering would be on the app server anyways, not the DB. Fair point, it wont work like this. Lets try something else...
SO the second idea was to create a PolyGlots table (name taken from http://weblogic.sys-con.com/node/102698?page=0,1), a PolyGlotTranslations table and a Culture table, where the PolyGlots would be referenced from each internationalized property. This way i wanted to say for example:
private static readonly CompiledExpression<Announcement, string> nameExpression
= DefaultTranslationOf<Announcement>
.Property(e => e.Name)
.Is(e=> e.NamePolyGlot.PolyGlotTranslations
.Where(t=> t.Culture.Code == Thread.CurrentThread.CurrentUICulture.Name)
.Single().Value
);
now unfortunately here i get an error that the Where() function cannot be translated to sql, what is a bit disappointing, as i was sure it will go through.
I guess it is failing, cause the IEntitySet is basically an IEnumerable, not IQueryable, am i right?
Is there another way to use the compiledExpressions class to achieve this goal?
Any help appreciated.
