I made conversion from EF4 to nHibernate and now have little problem with inheritence.
My entities and mappings:
public class User
{
public virtual int Id { get; set; }
public virtual string UserName { get; set; }
}
public class Account
{
public virtual int Id { get; set; }
public virtual User User { get; set; }
}
public class Member : User
{
public virtual string SpecialPropForMember { get; set; }
}
public class UserMap : ClassMap<User>
{
public UserMap()
{
Id(x => x.Id);
Map(x => x.UserName);
}
}
public class AccountMap : ClassMap<Account>
{
public AccountMap()
{
Id(x => x.Id);
References(x => x.User);
}
}
public class MemberMap : SubclassMap<Member>
{
public MemberMap()
{
Map(x => x.SpecialPropForMember);
}
}
My passed test:
[Test]
public void TestMemberUserInheritence()
{
User newUser = new User()
{
UserName = RandomValues.String()
};
Member newMember = new Member()
{
SpecialPropForMember = "special"
};
Account newAccount = new Account()
{
User = newMember
};
Member member = account.User as Member;
Assert.IsNotNull(member);
}
and failed test:
[Test]
public void TestMemberUserInheritenceFromNHibernate()
{
User newUser = new User()
{
UserName = RandomValues.String()
};
UsersService().AddUser(newUser);
Member newMember = new Member()
{
SpecialPropForMember = "special"
};
MemberService().Add(newMember);
Account newAccount = new Account()
{
User = newMember
};
AccountService().Add(newAccount);
Account account; ;
using (var session = DataAccess.OpenSession())
{
account = session.Linq<Account>().First();
}
Member member = account.User as Member;
Assert.IsNotNull(member);
}
Could someone explain me why NH don't resolve properly inheritance ?
The same issue is for table per class and table per hierarchy.
It's because of the way that NHibernate provides lazy loading. Value of account.User in your failing test is actually a proxy object. This means, that when you're loading account, the user is not fetched from DB until you access any of it's properties (unless you state so explicitly in your query). This means, that when NHibernate creates the proxy object, it does not know what is actual type of this object, and it creates proxy object that derives directly from User class. I've gone into more details in my anwser to this question: Force lazy entity to load real instance.
There is a mapping option "lazy = no-proxy" in NHibernate for the property that should fix the problem. I am not sure if it is available in Fluent NHibernate.
Read this blog post for more details
http://ayende.com/blog/4378/nhibernate-new-feature-no-proxy-associations
Related
I've got a domain model with collection of owned types. When I try to add more than one object in the ownedtyped collection? I get an exception:
System.InvalidOperationException: 'The instance of entity type 'ChildItem' cannot be tracked because another
instance with the key value '{NameId: -2147482647, Id: 0}' is already being
tracked. When replacing owned entities modify the properties without changing
the instance or detach the previous owned entity entry first.'
How can it be solved?
UPDATED
My domain classes:
public class Parent
{
public int Id { get; set; }
public Child Name { get; set; }
public Child ShortName { get; set; }
}
public class Child
{
public List<ChildItem> Items { get; set; }
}
public class ChildItem
{
public string Text { get; set; }
public string Language { get; set; }
}
My DbContext:
public class ApplicationContext : DbContext
{
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Parent>()
.OwnsOne(c => c.Name, d =>
{
d.OwnsMany(c => c.Items, a =>
{
a.HasForeignKey("NameId");
a.Property<int>("Id");
a.HasKey("NameId", "Id");
a.ToTable("ParentNameItems");
})
.ToTable("ParentName");
})
.ToTable("Parent");
modelBuilder.Entity<Parent>()
.OwnsOne(c => c.ShortName, d =>
{
d.OwnsMany(c => c.Items, a =>
{
a.HasForeignKey("NameId");
a.Property<int>("Id");
a.HasKey("NameId", "Id");
a.ToTable("ParentShortNameItems");
})
.ToTable("ParentShortName");
})
.ToTable("Parent");
}
}
Usage:
static void Main(string[] args)
{
var context = new ApplicationContext();
var parent = new Parent()
{
Name = new Child()
{
Items = new List<ChildItem>()
{
new ChildItem() { Text = "First value", Language = "en-en"},
new ChildItem() { Text = "Second value", Language = "en-en"}
}
},
ShortName = new Child()
{
Items = new List<ChildItem>()
{
new ChildItem() { Text = "First short value", Language = "en-en"},
new ChildItem() { Text = "Second short value", Language = "en-en"}
}
}
};
context.Set<Parent>().Add(parent);
context.SaveChanges();
}
Well, first of all you classes don't make sense. If anything it should be
public class Parent
{
public int Id { get; set; }
public List<Child> Children { get; set; }
}
a parent should have many children (or none possibly, empty list maybe?). What about the child's name and id, doesn't he have one of each ? also maybe a ParentId maybe something like
public class Child
{
public virtual List<ChildItem> Items { get; set; } //why virtual? you planning to inherit?
public string Name {get; set; }
public int Id {get; set; }
public int ParentId {get; set; }
}
That looks a little better, I should think. The database should have matching tables. and let's be honest EF (Entity Framework) auto create will do 99% of the work for you, so please use it.
Problem is solved. It was in line
a.HasKey("NameId", "Id");
in OnModelCreating method.
I used an example where was written abount configuring Collections of owned types.
After deleting "NameId" field from Key definition
a.HasKey("Id");
everything works fine now.
Entities:
public class Entity
{
public int Id { get; set; }
}
public class User : Entity
{
public string Name { get; set; }
public Company Company { get; set; }
}
public class Company : Entity
{
public string Name { get; set; }
}
Dto's:
public class EntityDto
{
public int Id { get; set; }
}
public class UserDto : EntityDto
{
public string Name { get; set; }
public int? CompanyId { get; set; }
}
So I want to map User to UserDto like User.Company == null => UserDto.CompanyId == null and vice versa.
That is my Automapper configuration:
Mapper.Initialize(configuration =>
{
configuration
.CreateMap<User, UserDto>()
.ReverseMap();
});
This works fine:
[Fact]
public void UnattachedUserMapTest()
{
// Arrange
var user = new User { Company = null };
// Act
var userDto = Mapper.Map<User, UserDto>(user);
// Assert
userDto.CompanyId.Should().BeNull();
}
but this test fails:
[Fact]
public void UnattachedUserDtoMapTest()
{
// Arrange
var userDto = new UserDto { CompanyId = null };
// Act
var user = Mapper.Map<UserDto, User>(userDto);
// Assert
user.Company.Should().BeNull();
}
Details:
Expected object to be <null>, but found
Company
{
Id = 0
Name = <null>
}
Doesn't work for me:
...
.ReverseMap()
.ForMember(user => user.Company, opt => opt.Condition(dto => dto.CompanyId != null));
and well as that (just for example):
...
.ReverseMap()
.ForMember(user => user.Company, opt => opt.Ignore());
Why does Automapper create nested object and how can I prevent it?
That "suddenly" bit is funny :)
configuration.CreateMap<User, UserDto>().ReverseMap().ForPath(c=>c.Company.Id, o=>o.Ignore());
You have a default MapFrom with CompanyId and that is applied in reverse. For details see this and a few other similar issues.
In the next version (on MyGet at the moment) you'll also be able to use
configuration.CreateMap<User, UserDto>().ReverseMap().ForMember(c=>c.Company, o=>o.Ignore());
This is a general question, I'm sure it's quite common, however I haven't found anything on it (or I don't know what to search for I guess).
I'm having the following entities in my project:
public class User
{
public virtual int Id { get; set; }
public virtual string FirstName { get; set; }
public virtual string LastName { get; set; }
public virtual Unit Unit { get; set; }
}
public class Unit
{
public virtual int Id { get; set;}
public virtual string Name { get; set;}
}
This is how I've done the Fluent NHibernate mappings:
public class UserMap : ClassMap<User>
{
public UserMap()
{
Id(x => x.Id).GeneratedBy.Identity().Column("UserId");
Map(x => x.FirstName);
Map(x => x.LastName);
References(x => x.Unit).Column("UnitId");
}
}
public class UnitMap : ClassMap<Unit>
{
public UnitMap()
{
Table("Unit");
LazyLoad();
Id(x => x.Id).GeneratedBy.Identity().Column("UnitId");
Map(x => x.Name).Column("Name").Not.Nullable();
HasMany(x => x.Users).KeyColumn("UnitId");
}
}
Now here is my question. How do I create a new User if I only have the user's unit Id not a full unit object, and the unit already exists in the database (created previously) ?
Something like this:
public class TestClass
{
// Adding a user to a unit example
public void SavingAUser(int unitId)
{
var user = new User
{
FirstName = "TestFirstName",
LastName = "TestLastName",
Unit = new Unit() // <-- I have only the Id of the unit I don't actually have a unit object here I don't want to query the DB to get the full object, I already have the Id
};
var userRepository = new UserRepository();
userRepository.Save(user);
}
}
How would I go about something like this. I hope I'm making sense, if not please let me know I'll throw in more clarifications. I'm also pretty certain that this is a very common scenario
You can return a proxy to the unit without fetching it.
var user = new User
{
FirstName = "TestFirstName",
LastName = "TestLastName",
Unit = Session.Load<Unit>(unitId)
}
You'll need to expose the session object.
Given is the following class hierarchy:
Class Diagram http://img535.imageshack.us/img535/4802/personusermanager.jpg
Additional info:
The Person class is not abstract.
A person could be a User, a Manager or something else that implements the IPerson interface.
The Person class must not have any knowledge about its child classes.
A child class could reside in another assembly.
It is also possible that a Person is a User and a Manager as wel. In that case the UserRepository must return a User object for the given PersonId and the ManagerRepository must return a Manager for the same PersonId.
It must also be possible to get the Person (base) part for all objects that implement the IPerson interface via a PersonRepository.
How can this be mapped within NHibernate?
We are using FluentNHibernate 1.2 and NHibernate 3.1.
In our current situation each class has its own table. So we have a Person table, a User table and a Manager table.
I have already tried the following options without success:
Mapping this with inheritence mapping (one table per subclass);
A join with Person in the mapping for User and Manager (without inheritance mapping);
A HasOne mapping with Person in the User and Manager mapping (without the join and inheritance mapping);
As you've no doubt discovered, it is easy enough to map inheritance like this: Person -> User, or Person -> Manager, or Person -> Manager -> User (or alternately, Person -> Manager -> User).
NHibernate does not allow you to promote/demote to or from a subclass. You'd have to run native SQL to promote or demote.
However, if you followed my initial "map" of your inheritance, you should have had an epiphany that using subclasses for what you are trying to do is an inappropriate solution for what you are trying to model. And that's only with two subclasses! What happens when you add more roles?
What you have is a Person, who can be a member of any number of roles, where roles are extensible. Consider this solution (Source on github: https://github.com/HackedByChinese/NHibernateComposition):
(Assume we have an Entity abstract class which handles equality, where to objects of the same type with the same ID are considered equal)
Project: Models
public class Person : Entity, IPerson
{
public virtual string FirstName { get; set; }
public virtual string LastName { get; set; }
public virtual IList<Role> Roles { get; protected set; }
public Person()
{
Roles = new List<Role>();
}
public virtual void AddRole(Role role)
{
if (Roles.Contains(role)) return;
role.Person = this;
Roles.Add(role);
}
public virtual void RemoveRole(Role role)
{
if (!Roles.Contains(role)) return;
role.Person = null;
Roles.Remove(role);
}
}
public interface IPerson
{
string FirstName { get; set; }
string LastName { get; set; }
Int32 Id { get; }
}
public abstract class Role : Entity
{
public virtual Person Person { get; set; }
public virtual string RoleName { get; protected set; }
}
public class User : Role
{
public virtual string LoginName { get; set; }
public virtual string Password { get; set; }
}
Project: Models.B
public class Manager : Role
{
public virtual string Division { get; set; }
public virtual string Status { get; set; }
}
Project: Models.Impl
I placed fluent mappings for both projects into one to save time. There could easily be separate mapping assemblies for Models and Models.B
public class PersonMap : ClassMap<Person>
{
public PersonMap()
{
Id(c => c.Id)
.GeneratedBy.HiLo("100");
Map(c => c.FirstName);
Map(c => c.LastName);
HasMany(c => c.Roles)
.Inverse()
.Cascade.AllDeleteOrphan();
}
}
public class RoleMap : ClassMap<Role>
{
public RoleMap()
{
Id(c => c.Id)
.GeneratedBy.HiLo("100");
DiscriminateSubClassesOnColumn<string>("RoleName");
References(c => c.Person);
}
}
public class UserMap : SubclassMap<User>
{
public UserMap()
{
DiscriminatorValue("User");
Join("User", joined =>
{
joined.Map(c => c.LoginName);
joined.Map(c => c.Password);
});
}
}
Project: Models.Impl.Tests
[TestFixture]
public class MappingTests
{
private ISessionFactory _factory;
#region Setup/Teardown for fixture
[TestFixtureSetUp]
public void SetUpFixture()
{
if (File.Exists("test.db")) File.Delete("test.db");
_factory = Fluently.Configure()
.Database(() => SQLiteConfiguration.Standard
.UsingFile("test.db")
.ShowSql()
.FormatSql())
.Mappings(mappings => mappings.FluentMappings
.AddFromAssemblyOf<PersonMap>())
.ExposeConfiguration(config =>
{
var exporter = new SchemaExport(config);
exporter.Execute(true, true, false);
})
.BuildSessionFactory();
}
[TestFixtureTearDown]
public void TearDownFixture()
{
_factory.Close();
}
#endregion
#region Setup/Teardown for each test
[SetUp]
public void SetUpTest()
{
}
[TearDown]
public void TearDownTest()
{
}
#endregion
[Test]
public void Should_create_and_retrieve_Person()
{
var expected = new Person
{
FirstName = "Mike",
LastName = "G"
};
using (var session = _factory.OpenSession())
using (var tx = session.BeginTransaction())
{
session.SaveOrUpdate(expected);
tx.Commit();
}
expected.Id.Should().BeGreaterThan(0);
using (var session = _factory.OpenSession())
using (var tx = session.BeginTransaction())
{
var actual = session.Get<Person>(expected.Id);
actual.Should().NotBeNull();
actual.ShouldHave().AllProperties().EqualTo(expected);
}
}
[Test]
public void Should_create_and_retrieve_Roles()
{
// Arrange
var expected = new Person
{
FirstName = "Mike",
LastName = "G"
};
var expectedManager = new Manager
{
Division = "One",
Status = "Active"
};
var expectedUser = new User
{
LoginName = "mikeg",
Password = "test123"
};
Person actual;
// Act
expected.AddRole(expectedManager);
expected.AddRole(expectedUser);
using (var session = _factory.OpenSession())
using (var tx = session.BeginTransaction())
{
session.SaveOrUpdate(expected);
tx.Commit();
}
using (var session = _factory.OpenSession())
using (var tx = session.BeginTransaction())
{
actual = session.Get<Person>(expected.Id);
// ignore this; just forcing the Roles collection to be lazy loaded before I kill the session.
actual.Roles.Count();
}
// Assert
actual.Roles.OfType<Manager>().First().Should().Be(expectedManager);
actual.Roles.OfType<Manager>().First().ShouldHave().AllProperties().But(c => c.Person).EqualTo(expectedManager);
actual.Roles.OfType<User>().First().Should().Be(expectedUser);
actual.Roles.OfType<User>().First().ShouldHave().AllProperties().But(c => c.Person).EqualTo(expectedUser);
}
}
If you want to constrain a Person to one instance of a particular role, just put a unique index and mess with the Equals method to check if Id is the same OR RoleName is the same.
You can easily get or check a user's role of any type:
if (person.Roles.OfType<User>().Any())
{
var user = person.Roles.OfType<User>().FirstOrDefault();
}
You can also query roles directly to look up their Person:
var peopleWhoAreManagersInDistrictOne = (from role in session.Query<Manager>()
where role.District == "One"
select role.Person);
You can also see that other assemblies can define additional roles. Manager is in a different assembly than Models.
So, you can see this will do everything you want plus more, despite the fact that it uses a different approach.
I have 2 classes that reference each other. It's a weird situation that our CRM needs.
I have an Organization and EmAddress tables and classes. The Organization inherits from Subscriber, which also has a table. I think this could be my problem, or the fact that I can't set Inverse on these because there is no "HasMany"...
The order of insert/update is ..
INSERT Email
INSERT Org
UPDATE Email to set Email.Subscriber
Email.Subscriber needs to be "NOT NULL", so this doesn't work. How can I change the order, I can't use Inverse because there is no list. Just 2 references.
public class Organization : Subscriber
{
public override string Class { get { return "Organization"; } }
EmAddress PrimaryEmailAddress {get;set;}
}
public class OrganizationMap : SubclassMap<Organization>
{
public OrganizationMap()
{
Table("Organization");
KeyColumn("Organization");
References(x => x.PrimaryEmail,"PrimaryEmailAddress").Cascade.SaveUpdate();
}
}
public EmAddressMap()
{
Id(x => x.Id, "EmAddress");
Map(x => x.EmailAddress, "eMailAddress");
References<Subscriber>(x => x.Subscriber,"Subscriber").LazyLoad().Fetch.Select().Not.Nullable();
/*not.nullable() throw s error. NHibernate INSERTS email, INSERTS org, UPDATES email. */
}
public class EmAddress
{
public virtual Guid Id { get; set; }
public virtual string EmailAddress { get; set; }
public virtual Subscriber Subscriber { get; set; }
}
//Implementation
var session = NHIbernateHelper.GetSession();
using(var tx = session.BeginTransaction())
{
var org = new Organization();
org.PrimaryEmail = new EmAddress(){Subscriber = org};
session.Save(org);
tx.commit();
}
This post might help:
http://ayende.com/blog/3960/nhibernate-mapping-one-to-one
Have only one side use many-to-one (Fluent: "References") and the other side uses one-to-one (Fluent: "HasOne").