NHibernate HasMany List remains empty when querying - nhibernate

Question

I've got a strange problem: Whenever I query an entity which has an IList, it remains empty. Querying the Language entity itself is possible... has this something to do with my composite key?
NHProf shows that BOTH entities are queried by sql, but for some reason, the results are not linked :-/
Here's some code:
public class Employee : User
{
public virtual string firstname { get; set; }
public virtual string lastname { get; set; }
public virtual string uid { get; set; }
public virtual string identity_provider
public virtual IList<Language> languages { get; set; }
}
The corresponding mapping:
public class EmployeeMap : ClassMap<Employee>
{
public EmployeeMap()
{
Table("employee");
Not.LazyLoad();
CompositeId()
.KeyProperty(x => x.uid)
.KeyProperty(x => x.identity_provider);
Map(x => x.firstname);
Map(x => x.lastname);
HasMany<Language>(x => x.languages)
.Table("employee_spoken_language")
.KeyColumns.Add("employee_uid","employee_identity_provider")
.Inverse().Cascade.All();
}
}
And for completeness, this is how "Language" is mapped:
public class LanguageMap : ClassMap<SpokenLanguage>
{
public LanguageMap()
{
Table("employee_spoken_language");
Not.LazyLoad();
CompositeId()
.KeyProperty(x => x.employee_uid)
.KeyProperty(x => x.employee_identity_provider)
.KeyProperty(x => x.name);
References(x => x.knowledge_level).Column("knowledge_level");
}
}
No matter what I change, my Employee Entity always shows language = {}!? This is really driving me crazy and I cannot find the error. I made sure that the sql for querying languages is executed! I made sure that data is in the database. And because I am using fluent, I also checked the hmb created:
<bag cascade="all" inverse="true" name="languages" table="employee_spoken_language">
<key>
<column name="employee_uid" />
<column name="employee_identity_provider" />
</key>
<one-to-many class="Jobportal.Language, wcf, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
</bag>
Hopefully someone can bring some light into this... Thanks in advance!
Regards,
Martin

Answer 1

This is an interesting one, I use nHibernate on all of my projects but rarely use composite keys. I used to do all of my mappings by hand (to learn) but now I use an Entity Developer tool to generate them. I have created comparable Employee and Language tables in my database with the same structure as yours and ran Entity Developer over them to generate the fluent mappings for you. I have listed these below. I don't see any vast difference but knowing how fussy nHibernate can be it might be worth a try. I may have some property lengths wrong etc but adjust as necessary to fit your specific needs.
For Employee:
public class EmployeeMap : ClassMap<Employee>
{
public EmployeeMap()
{
Schema(#"dbo");
Table(#"Employees");
LazyLoad();
CompositeId()
.KeyProperty(x => x.Uid, set => {
set.Type("String");
set.ColumnName("uid");
set.Length(50);
set.Access.Property(); } )
.KeyProperty(x => x.IdentityProvider, set => {
set.Type("String");
set.ColumnName("identity_provider");
set.Length(50);
set.Access.Property(); } );
Map(x => x.Firstname)
.Column("firstname")
.CustomType("String")
.Access.Property()
.Generated.Never()
.CustomSqlType("varchar")
.Not.Nullable();
Map(x => x.Lastname)
.Column("lastname")
.CustomType("String")
.Access.Property()
.Generated.Never()
.CustomSqlType("varchar")
.Not.Nullable();
HasMany<Language>(x => x.Languages)
.Access.Property()
.AsSet()
.Cascade.None()
.LazyLoad()
.Inverse()
.Generic()
.KeyColumns.Add("uid", mapping => mapping.Name("uid")
.SqlType("varchar")
.Not.Nullable()
.Length(50))
.KeyColumns.Add("identity_provider", mapping => mapping.Name("identity_provider")
.SqlType("varchar")
.Not.Nullable()
.Length(50));
}
}
For Language:
public class LanguageMap : ClassMap<Language>
{
public LanguageMap()
{
Schema(#"dbo");
Table(#"Languages");
LazyLoad();
CompositeId()
.KeyProperty(x => x.Uid, set => {
set.Type("String");
set.ColumnName("uid");
set.Length(50);
set.Access.Property(); } )
.KeyProperty(x => x.IdentityProvider, set => {
set.Type("String");
set.ColumnName("identity_provider");
set.Length(50);
set.Access.Property(); } )
.KeyProperty(x => x.Name, set => {
set.Type("String");
set.ColumnName("name");
set.Length(50);
set.Access.Property(); } );
References(x => x.Employee)
.Class<Employee>()
.Access.Property()
.Cascade.None()
.LazyLoad()
.Columns("uid", "identity_provider");
}
}
Let me know if these work any better, if not I will generate some test data and try and run some queries against these tables using the mappings for you.
One other thing to consider is to make sure you are working with the latest version of nHibernate.