Is it possible to have two keys in the same class?

Question

I have a question. I don't really know if it's possible. I'm working on an MVC application and part of the model look like this:

public class EmployeeNewspaper
{
    public string Name { get; set; }
    [Key]
    public string Appendage { get; set; }
    public string SourceInformationName { get; set; }
}

So my question is: Is it possible to have two keys in the same class? Or what can I do? I need to have the name and the appendage unique. Is it possible?

It's not entirely clear what the question is - is this an entity framework model or a standard MVC model? If it's a standard MVC model, do you want your unique-ness to be enforced by your code or in your user interface? (e.g. do you want a runtime error or a validation error if a duplicate is added... to something?) - if you can clarify where you want to enforce uniqueness it would be useful as the approach will differ (DB keys, hashes/equality comparer, validation rules etc) — Charleh, Jul 26 '16 at 13:40
Its an entity framework model. I want to show to the user that unique information — SomeAnonymousPerson, Jul 26 '16 at 13:46
When I run the stored procedure in the DB I have the correct information. But when I pass the information to the model, as I only have the key in the Appendage, it it has different names, its showing me the same name in any case. So I need to make the name and the appendage key (together) both of us in any case. Did I explain myself? — SomeAnonymousPerson, Jul 26 '16 at 13:48
You want a composite key then: http://stackoverflow.com/questions/14873169/creating-composite-key-entity-framework — Charleh, Jul 26 '16 at 13:56

score 1 · Accepted Answer · edited May 23 '17 at 12:06

1

Thanks @Charle I was actually looking for composite key and the answer is:

public class EmployeeNewspaper
{
    [Key][Column(Order = 0)]
    public string Name { get; set; }
    [Key][Column(Order = 1)]
    public string Appendage { get; set; }
    public string SourceInformationName { get; set; }
}

edited May 23 '17 at 12:06

Community

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answered Jul 26 '16 at 16:38

SomeAnonymousPerson

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score 0 · Answer 2 · answered Jul 26 '16 at 13:37

0

You could use a Guid and get a Globally Unique IDentifier.

But you will need to be aware that using this:

Guid MyID = new Guid();

will result in an all-zeros(empty) ID.

So you will need to use it this way:

Guid MyID = Guid.NewGuid();

answered Jul 26 '16 at 13:37

Khalil Khalaf

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How this does answer the question? – Maarten Jul 26 '16 at 13:41
How can I assign the Name and the Appendage to the GUID?, thanks! – SomeAnonymousPerson Jul 26 '16 at 13:41
2

This gives you a unique ID for the instance (aside from the reference itself) but does not enforce uniqueness for any fields.. – Charleh Jul 26 '16 at 13:42
I don't really understand. There Im only creating the guid variable, but I need to assign it, right? – SomeAnonymousPerson Jul 26 '16 at 13:45
@SomeAnonymousPerson I think I misunderstood the question. Anyway using `Guid MyID = new Guid(Appendage);` will initialize a new instance of the Guid structure by using the value represented by the specified string. Hope this helps – Khalil Khalaf Jul 26 '16 at 13:48

Is it possible to have two keys in the same class?

2 Answers2