Question

I have a query where I am only interested in the row count, however the query that NHibernate produces does not work with Sybase. I already have a custom Sybase dialect, but I can’t find where to override the rowcount.

Given the following code:

var a = from b in table where b.something = 5 select b
var rows = a.Count

Generates an SQL similar to this:

select cast(count(*) as INTEGER) as p1 from table

I don’t get why NHibernate wants to cast the count result, nor how I can override the dialect or elsewhere so NHibernate doesn’t include the cast. The result of a count is castable to integer anyways.

If I however use QueryOver, things work perfectly. The problem then however, is that one off my conditions is dependent on the length of a string (yes, the db design could be better, but I can currently not change it). Using linq to call .Length on a string in the conditions work. However I can’t use the string length as a condition in the QueryOver expressions. I also need a contains operation, which works with linq, but not QueryOver.

Is there a way to override how the Count query is generated, so it will work?
I am only interested if there is any rows matching, not the count, is there a different way of doing that?
Can instead the QueryOver? interface to use the SQL length and in operators?

Answer 1

You can understand if there are any rows matching by using Any function like this:

var a = from b in table where b.something = 5 select b; 
var isMatch = a.Any();