c# - Fluent NHibernate Where on Empty String -

i'm applying .where()-restriction on iqueryover<t,t> in fluentnh, such:

.where(x => x.col1 == null || x.col1 == ""); 

which generates following sql:

where (col1 null or col1 = null) 

how can make nh understand empty string means empty string?

you can write where clause this:

.where(restrictions.on<classtype>(obj => obj.col1).isnull ||        restrictions.on<classtype>(obj => obj.col1).islike(@"")) 

alternatively, if you're doing on several queries should consider creating query extension:

public static class queryextention {     public static iqueryover<e, f> wherestringisnullorempty<e, f>(this iqueryover<e, f> query, expression<func<e, object>> expression) {         var property = projections.property(expression);         var criteria = restrictions.or(restrictions.isnull(property),                                        restrictions.eq(property, string.empty));         return query.where(criteria);     } } 

then should able create like:

.queryover<classtype>() .wherestringisnullorempty(obj => obj.col1)