Question

I’m trying to do a map which I don’t know if is supported in NHibernate.

I have a table A for which I have a mapping in Fluent NHibernate.
I have another table called B in which I have to search for A.Id . If I find this Id in this table than I have to set a bool property in the mapping for class A to true, otherwise to false.

Between table A and table B there is a one to one relationship represented in the mapping with a HasOne method.
The trouble is that HasOne don’t have a CustomType method that I can use to convert the result to a bool property.

I would also be fine with casting the value to a bit or int from the mapping but I don’t know how to do that.

Does anyone know if this is possible and if yes how can be done ?

Thank you, Mosu.

Answer 1

Formula is made for such a scenario

Map(x => x.BooleanProperty).Formula("SELECT true IF EXISTS (SELECT 1 FROM B WHERE B.A_id = Id)");

Edit:

another approach (not tested)

// public AMap()
Join("TableB", join =>
{
    join.KeyColumn("A_id");
    join.Optional();
    Map(x => x.BooleanPropery, "someBcolumn").Not.Insert().Not.Update().CustomType<NullToFalseElseTrue>();
});

// class A
public virtual bool BooleanPropery { get; private set; }