Mapping two classes to the same table in different environments

Question

Let's say I have this Table:

Users
ID PK
NAME
IS_REAL

And I have this class for my front-end program (On the internet)

Class User
{
    Int ID {get;set;}
    string Name {get;set;}
}

And I also want to have another class for my back-end program (On the intranet)

Class MUser : User
{
    bool IsReal {get;set;}
}

Is there a way I can use my mapping for User class, So if one of my fields change, I will only have to change in one place instead of duplicating the mapping?

Thanks in advance,
Amir.

EDIT:

Just for clarification, The two environments are disconnected from one another, and I have the "Is_Real" Property on only one side (The intranet environment)

score 0 · Answer 1 · edited Jan 08 '16 at 09:25

0

http://nhibernate.info/doc/nh/en/index.html#inheritance-tableperconcreate-polymorphism

Notice that nowhere do we mention the IPayment interface explicitly. Also notice that properties of IPayment are mapped in each of the subclasses. If you want to avoid duplication, consider using XML entities (e.g. [ ] in the DOCTYPE declartion and &allproperties; in the mapping).

edited Jan 08 '16 at 09:25

Owen Pauling

11,349
20
53
64

answered Jun 07 '12 at 07:22

kalki

516
2
10

Each class here is mapped to a different table... I need the classes to be mapped to the same table. I also don't have a discriminator... – Amir Jun 07 '12 at 07:52
well that was just a pointer. You need define your reusable xml entities then use them in your hbm's that is if you are using xml based mappings. http://www.quackit.com/xml/tutorial/xml_creating_entities.cfm – kalki Jun 07 '12 at 08:40

score 0 · Answer 2 · answered Jun 07 '12 at 07:33

0

The idea is to Use Table per hierarchy mapping. But in this case your table should contain additional Discriminator column, so NHibernate could differentiate records in DB by your Domain classes using Discriminator Value.

To do that please use something like code below:

public class UsersMap : ClassMapping<Users>
{
        public UsersMap()
        {
            Table("Users");
            Id(u => u.Id, args => args.Generator(Generators.Guid));
            Property(u => u.Name, args => args.NotNullable(true));
            Discriminator(t => {
                        t.Force(true);
                        t.Insert(true);
                        t.Length(32);
                        t.NotNullable(true);
                        t.Type(NHibernateUtil.String);
                        t.Column("Discriminator");
                    });
            DiscriminatorValue("User");
        }
}

public class MUserMap : SubclassMapping<MUser>
{
        public MUserMap()
        {
            Property(u => u.IsReal, args => args.NotNullable(true));
            DiscriminatorValue("MUser");
        }
}

answered Jun 07 '12 at 07:33

Anton L

412
4
12

But I don't need to differentiate between records, I want all records to be fetched in both entities, the only difference is that I don't have the "Is_Real" property in the internet – Amir Jun 07 '12 at 07:48
@Amir Then this is not a question of mapping. This is rather a question of App design. You could have on a domain layer full User class with IsReal property and with corresponding mapping. The in different applications you could have separate classes User (for Internet) and MUser for intranet on App layer. And use App Services to map from Domain layer user to App layer users. – Anton L Jun 07 '12 at 08:30
@Amir if you do not need to display a detail of an entity w.r.t a particular view then do not display it so. The Only benefit you would get by mapping a table to different entities is for query projection, that too can be easily achieved via scalar queries. – kalki Jun 07 '12 at 08:38
I have edited my question, as you can see I can't use a service to transfer object between layers... – Amir Jun 07 '12 at 12:26
@Amir I din't mean a phisical Service (like Web or Windows Service). I meant that you could create a Domain project which will be shared between your 2 applications. And domain project will contain your User entity with all it's fields. Then each application will have it's own Application project which will reference Domain and have it's own User entity (internetUser or Intranet user). And by Service I meant a class which will use Domain.User to create Internet/Intranet.User. this will separate your end user application logic from common domain logic. – Anton L Jun 08 '12 at 10:42

Mapping two classes to the same table in different environments

2 Answers2