Restful rails

I have some questions regarding restful rails applications.
Is the concept of restful so tied to the database ?

What if a application does not use a database at all or if the
application is using a legacy database which you cannot modify or does
not have the concept of ids. How will restful urls and crud come into
this picture.

REST has nothing to do with the database, it's just a convention
oriented around HTTP verbs and default actions associated with them.
That is, it's between a browser (or other client) and the controllers.


It's more about resources than the database. They're not one to one,
but the way most rails models are designed usually, they're very close
to a resource. For instance, you may have a product resource, which
might have an attribute called name. The data for that might not
actually be inside the products table, or perhaps your product
resource might aggregate several associations of the product model.
Either way there's no implicit direct coupling of models with
resources, but more often they tend to be close. Hope that helps.

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