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Comment by rorylaitila | Hacker News Reader

Good luck. This is not new. Back in the Enterprise OOP era, there was a fad of developing universal data entities. Everyone eventually learned that there is no such thing as a universal entity. The semantic meaning of the data model depends on the user context, not the producer context. A "Movie" is not the same thing to the Finance team, Acquisition team, Infrastructure team, or Customer. There is not even always a common identifier, let alone common fields, let alone common meaning of the fields.

Edit: The more I read this article the more I hear this voice https://www.youtube.com/watch?v=y8OnoxKotPQ

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UDA does not believe in the existence of universal data entities. We embrace the idea that 2+ teams may have different opinions on how to represent the world. We are focused on the discovery of existing entities across systems and their reusability through extensibility. We believe that automation of the projections will be key for teams to align on defining some entities, where it makes sense.

> A "Movie" is not the same thing to the Finance team, Acquisition team, Infrastructure team, or Customer.

Shouldn’t it be?

No, because context and use defines the meaning. To the data team, a "Movie" might mean a file on disk. To the finance team, a "Movie" might mean a contract to a studio. To the Customer, a "Movie" is something they watch. That each of these contexts can use the term "Movie" does not actually mean they share anything in common. We could have called them "Files", "Contracts" and "Watchables" instead.

When people embark on 'universal' data definitions, conversations of the type "But is it reaaalllly a Movie??" are an endless source of confusion.

Alternatively, the process of defining these global definitions exposes exactly this conflict and leads to common definitions of "Files", "Contracts" and "Watchables" instead of 3 conflicting definitions of "Movies"?

The conflict will definitely help define the terms. Maybe they will all choose "Movie", maybe not. Just there is no universally ideal term that represents a concept for all users for all time. It's a common error to seek such universal definitions.

Exactly. In UDA, each Movie entity belongs to a specific business domain. Universality isn't an inherent truth, it's a social alignment within a group, useful only to the extent that it helps solve shared problems.

No, why would the finance team care for the cover of a movie or the available subtitles? If everyone would have the same definition, changing some thing about a movie will need a change in every consumer who doesn't actually care.

A unique identifier for a movie is the same thing, like an ISBN number. What the label means in each area is going to be different. That said, some things like "director", "budget" are immutable properties of a movie but are absolutely irrelevant for the business areas and the duplication of these properties in different domains is fundamentally not that big of a deal

Wittgenstein sends his regards

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