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Comment by injb | Hacker News Reader

The issue I'm talking about is allowing clients to make arbitrary queries via GQL. Maybe I've misunderstood it, but that's how I've seen it used before. If clients can do that, then they need to know about the model. And if they can't then I'm not sure what GQL does that REST doesn't do.

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My understanding is "arbitrary queries" <> "arbitrary _database_ queries". So you can have some abstract "graph" that can be queried, and separately implement "resolvers" (IIRC) that actually tie parts of the graph to actual queries. (So there is a layer of indirection.)

What you get is a way for clients to tell you precisely what fields it needs and a way for it to coalesce what would be multiple api calls in a REST world into a single request.

Thanks, that's a more nuanced understanding of it than I had. Still, when I try to think about keeping that model in sync with the real underlying model, it scares me.

It sounds to me like there is still bound to be some correlation between querying flexibility on the client side, and coupling between the client and server. But that is OK in many cases and in fact is how many REST apis are already being implemented.

GraphQL exposes your backend model the same way your json response to a REST api exposes the backend model - they dont. It's up to your REST api to assemble data from the database (or elsewhere) and return them in a structured format.

GraphQL resolvers do the same. You can hit another API, query a database, or return file data. It's up to you what you want each field to resolve to.

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