'Defining multiple Id columns using Marten?

I'm currently using the default Id implementation of Marten for this Object fe

    public class DbOBject
    {
        public string Id { get; set; }
        public string Name { get; set; }
        public int Type { get; set; }
   }

Now I want to define the Id and the Type column als Identifier, is this possible?

c++sharp


Solution 1:[1]

I don't believe there's a fully straightforward way to go about it.

Marten requires one Id field (or a property marked as an identifier).

I'd personally create a new field that is a composite of Id and Type (using concatenation or whatever you find most readable). And then use it as an identity.

If you're happy with implementing Marten interfaces and insist on a cleaner solution, I suggest you read these docs:

https://martendb.io/documents/identity.html#custom-identity-strategies

The links for interfaces and implementations are broken, but here's a working link to Marten's Identity generation:

https://github.com/JasperFx/marten/tree/master/src/Marten/Schema/Identity

This, however, will require you to have a separate key generator just for this specific class, which may actually make your code less readable (given that you should also configure a specific store just for it, in order to use the new custom generator).

Solution 2:[2]

Thanks, I've implemented the first solution 

  public class DbOBject
    {
        public string Id { get { return BusinessValue + "_" + Type.ToString(); } }
        public string Name { get; set; }
        public string BusinessValue{ get; set; }
        public int Type { get; set; }
   }

The Id was an unique business value that turned out not to be that unique. So I added the busisess value as a property and used the id as a combination of that business value and the type.

Sources

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Source: Stack Overflow

Solution Source
Solution 1 Phill
Solution 2 Werner Kellens

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