I'm applying a .Where()-restriction on an IQueryOver<T,T> in FluentNH, as such:
.Where(x => x.Col1 == null || x.Col1 == "");
Which generates the following SQL:
WHERE (Col1 IS NULL OR Col1 = NULL)
How can I make NH understand that empty string means empty string?
You can write your Where clause like this:
.Where(Restrictions.On<ClassType>(obj => obj.Col1).IsNull ||
Restrictions.On<ClassType>(obj => obj.Col1).IsLike(@""))
Alternatively, if you're doing this on several queries you should consider creating a 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 you should be able to create something like:
.QueryOver<ClassType>()
.WhereStringIsNullOrEmpty(obj => obj.Col1)
"" to NULL?