I can successfully implement the Soundex function. Not exactly in the same
easy way as you descripe, is the LingExtensionMethodAttribute just supposed
to tell NHibernate to use an SQL method with the exact same name as the C#
extension? I really think it should be that easy in a good design but
atleast I can´t get that to work instead of the attribute I can override
this method and I will have a working Soundex function (after some
registration is done)
public override HqlTreeNode BuildHql(MethodInfo method, Expression
targetObject, ReadOnlyCollection<Expression> arguments, HqlTreeBuilder
treeBuilder, IHqlExpressionVisitor visitor)
{
return treeBuilder.MethodCall("SOUNDEX", new[]
{
visitor.Visit(arguments[1]).AsExpression()
});
}
This works, the problem with MATCH() AGAINST() is that it´s basically two
method calls that works together and I´m not able to pass two methods to
the MethodCall function.
Den fredagen den 6:e juni 2014 kl. 16:23:13 UTC+2 skrev Ricardo Peres:
>
> Yes:
>
> [LinqExtensionMethod]public static String Soundex(this String input)
> {
> throw new NotImplementedException();
> }
>
>
> And you can call it like this (in SQL Server, because of the SOUNDEX
> function, but can be adapted to any server):
>
> var soundexName = session.Query<Customer>().Select(x =>
> x.Name.Soundex()).First();
>
>
> Let me know if this helps!
>
> RP
>
>
> On Friday, June 6, 2014 1:38:16 PM UTC+1, Gunnar Liljas wrote:
>>
>> No, it's possible to create custom SQL with it as well, since you can
>> register custom functions. Not sure about this particular syntax though.
>>
>> /g
>>
>> On 5 jun 2014, at 20:54, Ricardo Peres <[email protected]> wrote:
>>
>> AFAIK, this method only works for translating custom extensions into HQL.
>> Since HQL does not support MATCH...AGAINST, there's nothing you can do.
>> One possible alternative could possibly be writing a custom function in
>> MySQL that would wrap MATCH...AGAINST and calling it from LINQ. That is
>> possible.
>>
>> RP
>>
>>
>> On Thursday, June 5, 2014 8:41:49 AM UTC+1, Joel Hervén wrote:
>>>
>>> I´ve tried to write a LINQ extension that executes the MySQL function
>>> MATCH(...,...) AGAINST(...). But I have not been able to translate it into
>>> appropriate HQL because of the "two functions" syntax.
>>>
>>> To have something to look at I wrote this method
>>>
>>> public override HqlTreeNode BuildHql(MethodInfo method, Expression
>>> targetObject, ReadOnlyCollection<Expression> arguments, HqlTreeBuilder
>>> treeBuilder, IHqlExpressionVisitor visitor)
>>> {
>>> var e1 = treeBuilder.MethodCall("MATCH", new[]
>>> {
>>> visitor.Visit(arguments[0]).AsExpression(),
>>> });
>>>
>>> var e2 = treeBuilder.MethodCall("AGAINST", new[]
>>> {
>>> visitor.Visit(arguments[1]).AsExpression(),
>>> });
>>>
>>> return
>>> treeBuilder.Equality(e1, e2);
>>> }
>>>
>>> The Equality method is obviously not the correct thing here but it will
>>> generate the SQL "MATCH(....)+AGAINST(....)" which is very close to correct
>>> except the + sign that shouldn´t be there. I have looked at the
>>> HqlTreeBuilder many times but I can´t find a working method to just add up
>>> the methods like needed here.
>>>
>>> So next thing was to look at the HqlTreeBuilder and try to extend with
>>> an alternative
>>>
>>> public class HqlDoubleMethod : HqlBooleanExpression
>>> {
>>> public HqlDoubleMethod(IASTFactory factory, HqlExpression lhs,
>>> HqlExpression rhs)
>>> : base(0, "", factory, lhs, rhs)
>>> {
>>> }
>>> }
>>>
>>> Calling this method instead of Equality results in a
>>> RewriteEmptyStreamException rule b
>>>
>>>
>>> Is it possible to implement this kind of function without modifying the
>>> Nhibernate-core?
>>>
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