How to get records in first table(projects) not present in second table(finances) with foreign key reference using nhibernate - nhibernate

Question

I'm trying to query on a simple data structure in nhibernate and MSSQL
dbo.Projects : Id(int, not null)
dbo.Finances : Id(int, not null), ProjectId(int,not null), foreign key references to dbo.projects
I want to get all the records in projects table that are not present in finances table where the finances table has a foreign key reference ProjectId.
I am migrating to (Fluent) Nhibernate 3 from EntityFramework?
//So far I have got here:
public IQueryable<ProjectModel> GetProjectsNotPresentInFinance()
{
var factory = Fluently.Configure()
.Database(MsSqlConfiguration
.MsSql2008
.ConnectionString(m_connectionString))
.Mappings(m => m.FluentMappings
.AddFromAssemblyOf<ProjectMap>()
).BuildSessionFactory();
using (var session = factory.OpenSession())
{
var allprojects = session.QueryOver<ProjectModel>();
var projectsToReturn = allprojects.List<ProjectModel>().AsQueryable();
//--- Something like : all the records not in finances table ---------
// .Where( proj => !db.Finances.Where(fin => fin.ProjectId == proj.Id).Any())
// .Select(project => new ProjectModel
// {
// Id=project.Id,
// ProjectName = project.ProjectName,
// });
return projectsToReturn;
}
}
public class FinanceModel
{
public virtual int Id { get; set; }
public virtual int ProjectId { get; set; }
}
public class ProjectModel
{
public virtual int Id { get; set; }
public virtual string ProjectName { get; set; }
}
public class ProjectMap:ClassMap<ProjectModel>
{
public ProjectMap() {
Table("Projects");
Id(x => x.Id);
Map(x => x.ProjectName);
}
}
public class FinanceMap : ClassMap<FinanceModel>
{
public FinanceMap()
{
Table("Finances");
Id(x => x.Id);
References(x => x.ProjectModel);
}
}
//-------------------------------------------------------
//This is an Equivalent working code Using EntityFramework :
public IQueryable<ProjectModel> GetProjectsNotPresentInFinance() {
IQueryable<ProjectModel> projectList = db.Projects
.Where( proj => !db.Finances.Where(fin => fin.ProjectId == proj.Id).Any())
.Select(project => new ProjectModel
{
Id=project.Id,
ProjectName = project.ProjectName,
});
return projectList;
}
//-------------------------------------------------------

Answer 1

On second thought, you may try this without changing anything to your mapping, using a subquery :
var notOrphanProjectIdsSubquery = QueryOver.Of<FinanceModel>()
.Select(x => x.ProjectId);
var orphanProjects = session.QueryOver<ProjectModel>()
.WithSubquery
.WhereProperty(x=>x.Id)
.NotIn(notOrphanProjectIdsSubquery)
.List();
----------------------- Initial answer
Assuming you have a mapped Finances Property in your Project class, and according to https://stackoverflow.com/a/14980450/1236044, it should be something like :
var orphanProjects = session.QueryOver<ProjectModel>()
.WhereRestrictionOn(x => x.Finances).IsEmpty()
.List();
I must confess I am not proficient with FluentNH. I guess the classes and mappings should be something like this, hoping I'm not setting you on the wrong track...
public class FinanceModel
{
public virtual int Id { get; set; }
public virtual int ProjectId { get; set; }
public virtual ProjectModel Project{get;set;}
}
public class ProjectModel
{
public virtual int Id { get; set; }
public virtual string ProjectName { get; set; }
public virtual IList<FinanceModel> Finances { get; set; }
}
public class ProjectMap:ClassMap<ProjectModel>
{
public ProjectMap() {
Table("Projects");
Id(x => x.Id);
Map(x => x.ProjectName);
HasMany(x => x.Finances);
}
}
public class FinanceMap : ClassMap<FinanceModel>
{
public FinanceMap()
{
Table("Finances");
Id(x => x.Id);
References(x => x.Project);
}
}