Fluent NHibernate Many to one mapping - nhibernate

Question

I am creating a NHibenate application with one to many relationship. Like City and State data.
City table
CREATE TABLE [dbo].[State](
[StateId] [varchar](2) NOT NULL primary key,
[StateName] [varchar](20) NULL)
CREATE TABLE [dbo].[City](
[Id] [int] primary key IDENTITY(1,1) NOT NULL ,
[State_id] [varchar](2) NULL refrences State(StateId),
[CityName] [varchar](50) NULL)
My mapping is follows
public CityMapping()
{
Id(x => x.Id);
Map(x => x.State_id);
Map(x => x.CityName);
HasMany(x => x.EmployeePreferedLocations)
.Inverse()
.Cascade.SaveUpdate();
References(x => x.State)
//.Cascade.All();
//.Class(typeof(State))
//.Not.Nullable()
.Cascade.None()
.Column("State_id");
}
public StateMapping()
{
Id(x => x.StateId)
.GeneratedBy.Assigned();
Map(x => x.StateName);
HasMany(x => x.Jobs)
.Inverse();
//.Cascade.SaveUpdate();
HasMany(x => x.EmployeePreferedLocations)
.Inverse();
HasMany(x => x.Cities)
// .Inverse()
.Cascade.SaveUpdate();
//.Not.LazyLoad()
}
Models are as follows:
[Serializable]
public partial class City
{
public virtual System.String CityName { get; set; }
public virtual System.Int32 Id { get; set; }
public virtual System.String State_id { get; set; }
public virtual IList<EmployeePreferedLocation> EmployeePreferedLocations { get; set; }
public virtual JobPortal.Data.Domain.Model.State State { get; set; }
public City(){}
}
public partial class State
{
public virtual System.String StateId { get; set; }
public virtual System.String StateName { get; set; }
public virtual IList<City> Cities { get; set; }
public virtual IList<EmployeePreferedLocation> EmployeePreferedLocations { get; set; }
public virtual IList<Job> Jobs { get; set; }
public State()
{
Cities = new List<City>();
EmployeePreferedLocations = new List<EmployeePreferedLocation>();
Jobs = new List<Job>();
}
//public virtual void AddCity(City city)
//{
// city.State = this;
// Cities.Add(city);
//}
}
My Unit Testing code is below.
City city = new City();
IRepository<State> rState = new Repository<State>();
Dictionary<string, string> critetia = new Dictionary<string, string>();
critetia.Add("StateId", "TX");
State frState = rState.GetByCriteria(critetia);
city.CityName = "Waco";
city.State = frState;
IRepository<City> rCity = new Repository<City>();
rCity.SaveOrUpdate(city);
City frCity = rCity.GetById(city.Id);
The problem is , I am not able to insert record. The error is below.
"Invalid index 2 for this SqlParameterCollection with Count=2."
But the error will not come if I comment State_id mapping field in the CityMapping file. I donot know what mistake is I did. If do not give the mapping Map(x => x.State_id); the value of this field is null, which is desired. Please help me how to solve this issue.

Answer 1

Few remarks:
Remove this State_id property from the City class and the mapping. You already have a State property so it makes no sense in your object model.
Those Jobs and EmployeePreferedLocations properties in the State class don't have any related columns/tables in your database (at least the one you've shown here) while you have mappings for them.