I tend to model things like this with Dicts, Sets, and a type alias for
each identifier. So, something like
type alias Model =
{ artists : Dict ArtistId Artist
, albums : Dict AlbumId Album
}
type alias ArtistId =
Int
type alias Artist =
{ id : ArtistId
, name : String
, albums : Set AlbumId
}
type alias AlbumId =
Int
type alias Album =
{ id : AlbumId
, name : String
, artists : Set ArtistId
}
This is optimized for querying, adding and updating both Artists and
Albums. Deletions require a bit more thought: You'll have to update all the
cross-reference Set's as well.
On Thursday, September 22, 2016 at 6:24:38 PM UTC-4, Dénes Harmath wrote:
>
> Hi everybody,
>
> in a typical model, there are cross-references: e.g. we have artists and
> albums, and the album refers to its artist. How do we model this in Elm? A
> possible approach is giving unique identifiers to objects and store the
> referred object's identifiers similar to the TodoMVC example - is this
> mechanism extracted to some library in a type-safe way?
>
> Thank you in advance,
> thSoft
>
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